Naphthalene derivative, material for organic electroluminescence device, and organic electroluminescence device using the same

ABSTRACT

A naphthalene derivative represented by the following formula (1) is provided. In the formula (1), Ar 1  to Ar 6  each represent a substituted or unsubstituted aromatic hydrocarbon cyclic group having 6 to 18 carbon atoms forming a ring. The substituted or unsubstituted aromatic hydrocarbon cyclic group has none of anthracene skeleton, pyrene skeleton, aceanthrylene skeleton and naphthacene skeleton. R 1  to R 3  each represent an alkyl group, a cycloalkyl group, an alkoxy group, a cyano group, a silyl group or a halogen atom. R 1  to R 3  each may be bonded in any position of a main-chain naphthalene skeleton or a main-chain benzene skeleton. a and b each represent an integer in a range of 0 to 4. l, m, n and p each represent  0  or  1 .

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a naphthalene derivative, a materialfor an organic electroluminescence device and an organicelectroluminescence device using the same.

2. Description of Related Art

An organic electroluminescence device (hereinafter called as organic ELdevice), which includes an organic emitting layer between an anode and acathode, has been known to emit light using exciton energy generated bya recombination of holes and electrons that have been injected into theorganic emitting layer.

Such an organic EL device, which has the advantages as a self-emittingdevice, is expected to serve as an emitting device excellent in luminousefficiency, image quality, power consumption and thin design.

In applying an emitting material to an organic EL device, a dopingmethod, according to which a dopant material is doped to a hostmaterial, has been known as a usable method.

In order to effectively generate exciton from injected energy andeffectively convert exciton energy into light emission, an organic ELdevice is arranged such that the exciton energy generated in a host istransferred to a dopant, and that the dopant emits light.

Examples of such a host and dopant are such condensed aromatic compoundseach having a naphthalene skeleton as disclosed in Document 1(JP-A-2007-84485), Document 2 (JP-A-2006-151966), Document 3(JP-A-2005-19219), Document 4 (JP-A-2005-8588), Document 5(JP-A-2004-18510), Document 6 (WO2007/46658) and Document 7(JP-A-2003-142267).

However, although there has been a demand for an organic EL device thatis free from pixel defects and excellent in luminous efficiency, heatresistance and lifetime, no material for an organic EL device or no hostmaterial has been found usable for providing such an excellent organicEL device.

On the other hand, in order to enhance internal quantum efficiency andachieve higher luminous efficiency, a phosphorescence material thatemits light using triplet exciton has been developed. Recently, therehas been a report on an organic device using phosphorescence emission.

Since the internal quantum efficiency can be enhanced up to 75% or more(up to approximately 100% in theory) by using such a phosphorescencematerial, an organic EL device having high efficiency and consuming lesspower can be obtained.

However, although exhibiting much higher luminous efficiency, such aconventional phosphorescent organic EL device has such a short lifetimeas to be practically inapplicable.

SUMMARY OF THE INVENTION

In view of the above problems, an object of the present invention is toprovide an organic EL device that is free from pixel defects andexcellent in luminous efficiency, heat resistance and lifetime, and toprovide a naphthalene derivative and a material for an organic EL devicecapable of realizing such an organic EL device.

After conducting concentrated studies in order to achieve such anobject, the inventors have found that an organic EL device that is freefrom pixel defects and excellent in efficiency, heat resistance andlifetime can be provided by using a naphthalene derivative representedby the following formula (I) as the material for the organic EL device,and reached the present invention.

A naphthalene derivative according to an aspect of the present inventionis represented by the following formula (I).

In the formula (1), Ar¹ to Ar⁶ each represent a substituted orunsubstituted aromatic hydrocarbon cyclic group having 6 to 18 carbonatoms forming a ring. The substituted or unsubstituted aromatichydrocarbon cyclic group has none of anthracene skeleton, pyreneskeleton, aceanthrylene skeleton and naphthacene skeleton. Ar¹ and Ar²each may be bonded in any position of a benzene skeleton.

R¹ to R³ each represent an alkyl group, a cycloalkyl group, an alkoxygroup, a cyano group, a silyl group or a halogen atom. R¹ to R³ each maybe bonded in any position of a main-chain naphthalene skeleton or amain-chain benzene skeleton.

a, b and c each represent an integer in a range of 0 to 4.

a represents the number of substituent(s) R¹ directly bonded to themain-chain benzene.

b represents the number of substituent(s) R² directly bonded to themain-chain naphthalene.

c represents the number of substituent(s) R³ directly bonded to themain-chain benzene.

l, m, n and p each represent 0 or 1.

R¹, R² and R³ each may be mutually the same or different.

When a, b and c each are independently 2 or more, the plurality of R¹may be mutually the same or different, the plurality of R² may bemutually the same or different, the plurality of R³ may be mutually thesame or different or the pluralities of R¹ to R³ may be the same as ordifferent from one another.

Ar¹ to Ar⁶ may be mutually the same or different.

When at least either one of l and n is 1, Ar¹ represents neither abenzene skeleton nor a naphthalene skeleton.

When at least either one of m and p is 1, Ar² represents neither abenzene skeleton nor a naphthalene skeleton.

The structure represented by (H-[Ar⁵]_(n)—[Ar³]_(l)—Ar¹—) is not thesame as the structure represented by (H—[Ar⁶]_(p)-[Ar⁴]_(m)—Ar²—).

When the naphthalene derivative has a structure in which two naphthaleneskeletons are consecutively bonded together, the structure of thenaphthalene derivative is represented by any one of formulae (1-A),(1-B), (1-C) and (1-D) as follows.

The naphthalene skeletons represented by the formulae (1-A), (1-B) and(1-C) each may have a substituent(s) in any suitable position(s) or maybe unsubstituted.

In the formula (1-D), R represents a substituent. R may represent asingle substituent or plural substituents. The substituent(s) may be inany position(s) of the two naphthalene skeletons. When R representsplural substituents, the plural substituents may be mutually the same ordifferent.

When the naphthalene derivative contains a plurality of unsubstituted9-phenanthrenes, the number of the unsubstituted 9-phenanthrenes is 3 ormore.

When Ar¹ to Ar⁶ each represent a phenanthrene skeleton, the phenanthreneskeleton is monovalent phenanthrene.

A material for an organic EL device according another aspect of thepresent invention contains the naphthalene derivative represented by theformula (I).

An organic EL device according to still further aspect of the presentinvention includes: a cathode; an anode; an organic thin-film layerprovided between the anode and the cathode, the organic thin-film layerincluding at least one layer, the at least one layer including anemitting layer, in which the at least one layer of the organic thin-filmlayer contains the naphthalene derivative represented by the formula(I).

According to the aspect(s) of the present invention, an organic ELdevice that is free from pixel defects and excellent in luminousefficiency, heat resistance and lifetime can be provided. In addition, anaphthalene derivative and a material for an organic EL device capableof realizing such an organic EL device can be provided.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 schematically shows an exemplary arrangement of an organic ELdevice according to an exemplary embodiment of the present invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENT(S)

Embodiment(s) of the present invention will be described below.

[Naphthalene Derivative]

A naphthalene derivative according to an aspect of the present inventionis represented by the following formula (I).

In the formula (1), Ar¹ to Ar⁶ each represent a substituted orunsubstituted aromatic hydrocarbon cyclic group having 6 to 18 carbonatoms forming a ring. The substituted or unsubstituted aromatichydrocarbon cyclic group has none of anthracene skeleton, pyreneskeleton, aceanthrylene skeleton and naphthacene skeleton. Ar¹ and Ar²each may be bonded in any position of a benzene skeleton.

R¹ to R³ each represent an alkyl group, a cycloalkyl group, an alkoxygroup, a cyano group, a silyl group or a halogen atom. R¹ to R³ each maybe bonded in any position of a main-chain naphthalene skeleton or amain-chain benzene skeleton.

a and b each represent an integer in a range of 0 to 4.

a represents the number of substituent(s) R¹ directly bonded to themain-chain benzene.

b represents the number of substituent(s) R² directly bonded to themain-chain naphthalene.

c represents the number of substituent(s) R³ directly bonded to themain-chain benzene.

l, m, n and p each represent 0 or 1.

R¹, R² and R³ each may be mutually the same or different.

When a, b and c each are 2 or more, the plurality of R¹ may be mutuallythe same or different, the plurality of R² may be mutually the same ordifferent, the plurality of R³ may be mutually the same or different orthe pluralities of R¹ to R³ may be the same as or different from oneanother.

Ar¹ to Ar⁶ may be mutually the same or different.

When at least either one of l and n is 1, Ar¹ represents neither abenzene skeleton nor a naphthalene skeleton.

When at least either one of m and p is 1, Ar² represents neither abenzene skeleton nor a naphthalene skeleton.

The structure represented by (H—[Ar⁵]_(n)—[Ar³]_(l)—Ar¹—) is not thesame as the structure represented by (H—[Ar⁶]_(p)—[Ar⁴]_(m)—Ar²—).

When the naphthalene derivative has a structure in which two naphthaleneskeletons are consecutively bonded together, the structure of thenaphthalene derivative is represented by any one of formulae (1-A),(1-B), (1-C) and (1-D) as follows.

The naphthalene skeletons represented by the formulae (1-A), (1-B) and(1-C) each may have a substituent(s) in any suitable position(s) or maybe unsubstituted.

In the formula (1-D), R represents a substituent. R may represent asingle substituent or plural substituents. The substituent(s) may be inany position(s) of the two naphthalene skeletons. When R representsplural substituents, the plural substituents may be mutually the same ordifferent.

When the naphthalene derivative contains a plurality of unsubstituted9-phenanthrenes, the number of the unsubstituted 9-phenanthrenes is 3 ormore.

When Ar¹ to Ar⁶ each represent a phenanthrene skeleton, the phenanthreneskeleton is monovalent phenanthrene.

In the present invention, “carbon atoms forming a ring” means carbonatoms for forming a saturated ring, an unsaturated ring or an aromaticring. On the other hand, “atoms forming a ring” means carbon atoms andheteroatoms for forming a heterocycle (including a saturated ring, anunsaturated ring and an aromatic ring).

The naphthalene derivative according to the aspect of the presentinvention can be favorably applied to a material for forming an organicEL device that is free from pixel defects and excellent in luminousefficiency, heat resistance and lifetime.

An organic compound having an anthracene skeleton, a pyrene skeleton, anaceanthrylene skeleton or an naphthacene skeleton is not preferablebecause such an organic compound generates less triplet exciton energyand because a phosphorescent organic EL device in which such an organiccompound is used can hardly emit light efficiently. Thus, it is notpreferable that Ar¹ to Ar⁶ each have any one of the skeletons listedabove.

In addition, since less triplet exciton energy is generated when Ar¹ toAr⁶ each contain more than 18 carbon atoms, a phosphorescent organic ELdevice in which such a naphthalene derivative is used can hardly emitlight efficiently.

Compounds in each of which two or more naphthalene skeletons areconsecutively bonded together in β positions and compounds each having ahighly-symmetrical structure exhibit such high crystallinity that thecompounds can hardly maintain high amorphousness when being formed intothin film(s).

As a solution, for instance, by:

(1) introducing torsional portion(s) into the molecule with thenaphthalene skeletons being bonded together in α positions;(2) introducing substituent(s) having steric hindrance; and/or(3) asymmetrically shaping the molecule,

crystallization of the compounds can be prevented, such that thinfilm(s) of high amorphousness can be formed.

According to the present invention, when the naphthalene derivative isstructured such that two naphthalene skeletons are consecutively bondedtogether, the naphthalene skeletons are bonded together in α positionsas represented by the formula (1-A), (1-B) or (1-C), so that thetorsional portion prevents the crystallization of the naphthalenederivative.

According further to the present invention, when two naphthaleneskeletons are bonded together in β positions, substituent(s) R arecontained as represented by the formula (1-D), such that sterichindrance of the substituent(s) R can prevent the crystallization of thenaphthalene derivative.

When the structure represented by (H—[Ar⁵]_(n)—[Ar³]_(l)—Ar¹—) is thesame as the structure represented by (H—[Ar⁶]_(p)—[Ar⁴]_(m)—Ar²—), themolecule becomes symmetric, so that crystallinity thereof becomes high.Thus, such a structure is not used in the present invention.

As described above, according to the present invention, thecrystallization of the compound within the layer of the organic ELdevice can be prevented by a combination of asymmetrically forming themolecule and introducing torsional position(s) in the molecule. Theprevention of the crystallization of the compound within the layer isindispensable for solving a problem(s).

When the naphthalene derivative contains a plurality of unsubstituted9-phenanthrenes as substituents, the number of the unsubstituted9-phenanthrenes is 3 or more. Thus, by introducing a plurality ofpartial structures each having a relatively large molecular weight, heatresistance can be enhanced.

Only a material that satisfies all of the above-described conditions canbe favorably applied as a material for forming an organic EL device thatis free from pixel defects and excellent in luminous efficiency, heatresistance and lifetime.

R¹ to R³ in the formula (1) each preferably represent an alkyl grouphaving 1 to 30 carbon atoms, a cycloalkyl group having 3 to 30 carbonatoms, an alkoxy group having 1 to 20 carbon atoms, a cyano group, asilyl group having 3 to 30 carbon atoms or a halogen atom.

Examples of the alkyl group having 1 to 30 carbon atoms are a methylgroup, ethyl group, propyl group, isopropyl group, n-butyl group,s-butyl group, isobutyl group, t-butyl group, n-pentyl group, n-hexylgroup, n-heptyl group, n-octyl group, hydroxymethyl group,1-hydroxyethyl group, 2-hydroxyethyl group, 2-hydroxyisobutyl group,1,2-dihydroroxyethyl group, 1,3-dihydroxyisopropyl group,2,3-dihydroxy-t-butyl group, 1,2,3-trihydroxypropyl group, chloromethylgroup, 1-chloroethyl group, 2-chloroethyl group, 2-chloroisobutyl group,1,2-dichloroethyl group, 1,3-dichloroisopropyl group,2,3-dichloro-t-butyl group, 1,2,3-trichloropropyl group, bromomethylgroup, 1-bromoethyl group, 2-bromoethyl group, 2-bromoisobutyl group,1,2-dibromoethyl group, 1,3-dibromoisopropyl group, 2,3-dibromo-t-butylgroup, 1,2,3-tribromopropyl group, iodomethyl group, 1-iodoethyl group,2-iodoethyl group, 2-iodoisobutyl group, 1,2-diiodoethyl group,1,3-diiodoisopropyl group, 2,3-diiodo-t-butyl group, 1,2,3-triiodopropylgroup, aminomethyl group, 1-aminoethyl group, 2-aminoethyl group,2-aminoisobutyl group, 1,2-diaminoethyl group, 1,3-diaminoisopropylgroup, 2,3-diamino-t-butyl group, 1,2,3-triaminopropyl group,cyanomethyl group, 1-cyanoethyl group, 2-cyanoethyl group,2-cyanoisobutyl group, 1,2-dicyanoethyl group, 1,3-dicyanoisopropylgroup, 2,3-dicyano-t-butyl group, 1,2,3-tricyanopropyl group,nitromethyl group, 1-nitroethyl group, 2-nitroethyl group,2-nitroisobutyl group, 1,2-dinitroethyl group, 1,3-dinitroisopropylgroup, 2,3-dinitro-t-butyl group and 1,2,3-trinitropropyl group.

Examples of the cycloalkyl group having 3 to 30 carbon atoms arecyclopentyl group, cyclohexyl group, cyclooctyl group, and3,5-tetramethylcyclohexyl group, among which cyclohexyl group,cyclooctyl group and 3,5-tetramethylcyclohexyl group are preferable.

The alkoxy group having 1 to 20 carbon atoms is a group represented by—OY. Examples of Y are a methyl group, ethyl group, propyl group,isopropyl group, n-butyl group, s-butyl group, isobutyl group, t-butylgroup, n-pentyl group, n-hexyl group, n-heptyl group, n-octyl group,hydroxymethyl group, 1-hydroxyethyl group, 2-hydroxyethyl group,2-hydroxyisobutyl group, 1,2-dihydroroxyethyl group,1,3-dihydroxyisopropyl group, 2,3-dihydroxy-t-butyl group,1,2,3-trihydroxypropyl group, chloromethyl group, 1-chloroethyl group,2-chloroethyl group, 2-chloroisobutyl group, 1,2-dichloroethyl group,1,3-dichloroisopropyl group, 2,3-dichloro-t-butyl group,1,2,3-trichloropropyl group, bromomethyl group, 1-bromoethyl group,2-bromoethyl group, 2-bromoisobutyl group, 1,2-dibromoethyl group,1,3-dibromoisopropyl group, 2,3-dibromo-t-butyl group,1,2,3-tribromopropyl group, iodomethyl group, 1-iodoethyl group,2-iodoethyl group, 2-iodoisobutyl group, 1,2-diiodoethyl group,1,3-diiodoisopropyl group, 2,3-diiodo-t-butyl group, 1,2,3-triiodopropylgroup, aminomethyl group, 1-aminoethyl group, 2-aminoethyl group,2-aminoisobutyl group, 1,2-diaminoethyl group, 1,3-diaminoisopropylgroup, 2,3-diamino-t-butyl group, 1,2,3-triaminopropyl group,cyanomethyl group, 1-cyanoethyl group, 2-cyanoethyl group,2-cyanoisobutyl group, 1,2-dicyanoethyl group, 1,3-dicyanoisopropylgroup, 2,3-dicyano-t-butyl group, 1,2,3-tricyanopropyl group,nitromethyl group, 1-nitroethyl group, 2-nitroethyl group,2-nitroisobutyl group, 1,2-dinitroethyl group, 1,3-dinitroisopropylgroup, 2,3-dinitro-t-butyl group and 1,2,3-trinitropropyl group.

The silyl group having 3 to 30 carbon atoms is preferably an alkylsilylgroup having 3 to 20 carbon atoms, an arylsilyl group or an aralkylsilylgroup, examples of which are trimethylsilyl group, triethylsilyl group,tributylsilyl group, trioctylsilyl group, triisobutylsilyl group,dimethylethylsilyl group, dimethylisopropylsilyl group,dimethylpropylsilyl group, dimethylbutylsilyl group,dimethyltertiarybutylsilyl group, diethylisopropylsilyl group,phenyldimethylsilyl group, diphenylmethylsilyl group,diphenyltertiarybutyl group and triphenylsilyl group.

Examples of the halogen atom represented by each of R¹ to R³ arefluorine, chlorine, bromine, iodine and the like.

R in the formula (1-D) preferably represents an alkyl group, acycloalkyl group, an alkoxy group, a cyano group, a silyl group or ahalogen atom.

Examples of a substituent for the above groups are the same as theexamples of R¹ to R³.

In the formula (1), Ar¹ to Ar⁶ each preferably represent a benzeneskeleton, a naphthalene skeleton, a fluorene skeleton, a phenanthreneskeleton, a fluoranthene skeleton, a triphenylene skeleton or a chryseneskeleton.

When Ar¹ to Ar⁶ each represents any one of the above-describedstructures, triplet energy gap becomes sufficiently large. Thus, anaphthalene derivative structured as such can be favorably applied as aphosphorescent host capable of transferring energy to a phosphorescentmaterial.

It should be noted that a “fluorescent host” and a “phosphorescent host”herein respectively mean a host combined with a fluorescent dopant and ahost combined with a phosphorescent dopant, and that a distinctionbetween the fluorescent host and phosphorescent host is notunambiguously derived only from a molecular structure of the host in alimited manner.

In other words, the fluorescent host herein means a material for formingfluorescent-emitting layer containing a fluorescent dopant, and does notmean a host that is only usable as a host of a fluorescent material.

Likewise, the phosphorescent host herein means a material for formingphosphorescent-emitting layer containing a phosphorescent dopant, anddoes not mean a host that is only usable as a host of a phosphorescentmaterial.

When Ar¹ to Ar⁶ in the formula (I) each has a substituent, preferableexamples of the substituent are an aryl group having 6 to 30 carbonatoms, an alkyl group having 1 to 30 carbon atoms, a cycloalkyl grouphaving 3 to 30 carbon atoms, an alkoxy group having 1 to 20 carbonatoms, a cyano group, a silyl group having 3 to 30 carbon atoms and ahalogen atom.

Examples of the aryl group having 6 to 30 carbon atoms are a phenylgroup, 1-naphthyl group, 2-naphthyl group, 1-phenanthryl group,2-phenanthryl group, 3-phenanthryl group, 4-phenanthryl group,9-phenanthryl group, 2-biphenylyl group, 3-biphenylyl group,4-biphenylyl group, p-terphenyl-4-yl group, p-terphenyl-3-yl group,p-terphenyl-2-yl group, m-terphenyl-4-yl group, m-terphenyl-3-yl group,m-terphenyl-2-yl group, o-tolyl group, m-tolyl group, p-tolyl group,p-t-butylphenyl group, p-(2-phenylpropyl)phenyl group,3-methyl-2-naphthyl group, 4-methyl-1-naphthyl group, 4-methyl-1-anthrylgroup, 4′-methylbiphenylyl group, and 4″-t-butyl-p-terphenyl-4-yl group.

The examples of the alkyl group having 1 to 30 carbon atoms, thecycloalkyl group having 3 to 30 carbon atoms, the alkoxy group having 1to 20 carbon atoms, the silyl group having 3 to 30 carbon atoms and thehalogen atom each are the same as the examples of R¹ to R³.

In the above formula (I), a sum of m, n, l and p (m+n+1+p) is preferablyin a range of 0 to 3.

When m+n+1+p is more than 3, a molecular weight of the naphthalenederivative becomes so large that the naphthalene derivative can hardlybe vapor-deposited. Thus, m+n+1+p is preferably 3 or less.

In the formula (I), a, b and c each preferably represent an integer in arange of 0 to 3, more preferably 0.

Examples of the naphthalene derivative according to the presentinvention are as follows.

[Material for Organic EL Device]

A material for an organic EL device according another aspect of thepresent invention contains the naphthalene derivative represented by theformula (I).

The material for an organic EL device according to the aspect of thepresent invention is preferably used as a host material of an emittinglayer.

By using the material containing the naphthalene derivative representedby the formula (I) as the host material of the emitting layer, theemitting layer can exhibit high efficiency and long lifetime.

[Organic EL Device]

Next, an organic EL device according to still further aspect of thepresent invention will be described.

An organic EL device according to still further aspect of the presentinvention includes: a cathode; an anode; and an organic thin-film layerprovided between the cathode and the anode. The organic thin-film layerincludes at least one layer, and the at least one layer of the organicthin-film layer includes an emitting layer. The at least one layer ofthe organic thin-film layer contains the material for an organic ELdevice according to the present invention.

A multilayer organic EL device may be exemplarily structured asanode/hole transporting layer (hole injecting layer)/emittinglayer/cathode, anode/emitting layer/electron transporting layer(electron injecting layer)/cathode, anode/hole transporting layer (holeinjecting layer)/emitting layer/electron transporting layer (electroninjecting layer)/cathode, or anode/hole transporting layer (holeinjecting layer)/emitting layer/hole blocking layer/electrontransporting layer (electron injecting layer)/cathode.

FIG. 1 schematically shows an arrangement of an exemplary organic ELdevice according to the present invention.

An organic EL device 1 includes a transparent substrate 2, an anode 3, acathode 4 and an organic thin-film layer 10 disposed between the anode 3and the cathode 4.

The organic thin-film layer 10 includes a phosphorescent emitting layer5 containing a host and a phosphorescent dopant. A layer such as a holeinjecting/transporting layer 6 may be provided between thephosphorescent emitting layer 5 and the anode 3 while a layer such as anelectron injecting/transporting layer 7 may be provided between thephosphorescent emitting layer 5 and the cathode 4.

In addition, an electron blocking layer may be provided to thephosphorescent emitting layer 5 adjacent to the anode 3 while a holeblocking layer may be provided to the phosphorescent emitting layer 5adjacent to the cathode 4.

With this arrangement, electrons and holes can be confined in thephosphorescent emitting layer 5, thereby enhancing probability ofexciton generation in the phosphorescent emitting layer 5.

It should be noted that the “hole injecting/transporting layer” hereinmeans “at least one of hole injecting layer and hole transporting layer”while “electron injecting/transporting layer” herein means “at least oneof electron injecting layer and electron transporting layer”.

In the organic EL device according to the present invention, theemitting layer preferably contains the material for an organic EL deviceaccording to the present invention as the host material. In addition,the emitting layer is preferably formed of a host material andphosphorescent material while the host material is the material for anorganic EL device according to the present invention.

An example of the phosphorescent material is a metal complex formed of ametal selected from a group consisting of 1 r, Pt, Os, Au, Cu, Re and Ruand a ligand. The phosphorescent material is preferably a compoundcontaining a metal selected from a group of iridium (Ir), osmium (Os)and platinum (Pt) because such a compound, which exhibits highphosphorescence quantum yield, can further enhance external quantumefficiency of the emitting device. The phosphorescent material is morepreferably a metal complex such as an iridium complex, an osmium complexor a platinum complex, among which an iridium complex and a platinumcomplex are more preferable and ortho metalation of an iridium complexis the most preferable. More preferable examples of ortho metalation ofa metal complex are iridium complexes and the like as follows.

In the organic EL device according to the present invention, theemitting layer contains the host material and the phosphorescentmaterial. Examples of the phosphorescent material are the above-showniridium complexes.

According to the present invention, the phosphorescent materialpreferably emits light with maximum wavelength of 520 nm to 700 nm, morepreferably 590 nm to 700 nm.

By doping the phosphorescent material (phosphorescent dopant) havingsuch an emission wavelength to the material for an organic EL deviceaccording to the present invention so as to form the emitting layer, theorganic EL device can exhibit high efficiency.

In the organic EL device according to the present invention, the holetransporting layer (or the hole injecting layer) included therein maycontain the material for an organic EL device according to the presentinvention. Alternatively, when the organic EL device according to thepresent invention includes at least either one of the electrontransporting layer and the hole blocking layer, at least either one ofthe electron transporting layer and the hole blocking layer may containthe material for an organic El device according to the presentinvention.

In the organic EL device according to the present invention, a reductivedopant may be contained in an interfacial region between the cathode andthe organic thin-film layer.

With this arrangement, the organic EL device can emit light withenhanced luminance intensity and have a longer lifetime.

The reductive dopant may be at least one compound selected from a groupof an alkali metal, an alkali metal complex, an alkali metal compound,an alkali earth metal, an alkali earth metal complex, an alkali earthmetal compound, a rare-earth metal, a rare-earth metal complex, arare-earth metal compound and the like.

Examples of the alkali metal are Na (work function: 2.36 eV), K (workfunction: 2.28 eV), Rb (work function: 2.16 eV), Cs (work function: 1.95eV) and the like, among which a substance having a work function of 2.9eV or less is particularly preferable. Among the above, the reductivedopant is preferably K, Rb or Cs, more preferably Rb or Cs, the mostpreferably Cs.

Examples of the alkali earth metal are Ca (work function: 2.9 eV), Sr(work function: 2.0 to 2.5 eV), Ba (work function: 2.52 eV), and thelike, among which a substance having a work function of 2.9 eV or lessis particularly preferable.

Examples of the rare-earth metal are Sc, Y, Ce, Tb, Yb and the like,among which a substance having a work function of 2.9 eV or less isparticularly preferable.

Since the above preferable metals have particularly high reducibility,addition of a relatively small amount of these alkali metals to anelectron injecting zone can enhance luminance intensity and lifetime ofthe organic EL device.

Examples of the alkali metal compound are an alkali oxide such as Li₂O,Cs₂O or K₂O, an alkali halogen compound such as LiF, NaF, CsF or KF andthe like, among which LiF, Li₂O and NaF are preferable.

Examples of the alkali earth metal compound are BaO, SrO, CaO, a mixturethereof such as Ba_(x)Sr_(1-x)O (0<x<1) or Ba_(x)Ca_(1-x)O (0<x<1) andthe like, among which BaO, SrO and CaO are preferable.

Examples of the rare-earth metal compound are YbF₃, ScF₃, ScO₃, Y₂O₃,Ce₂O₃, GdF₃, TbF₃ and the like, among which YbF₃, ScF₃ and TbF₃ arepreferable.

The alkali metal complex, the alkali earth metal complex and therare-earth metal complex are not specifically limited, as long as atleast one of alkali metal ion, alkali earth metal ion and rare-earthmetal ion is contained therein as metal ion. Ligand for each of thecomplexes is preferably quinolinol, benzoquinolinol, acridinol,phenanthridinol, hydroxyphenyl oxazole, hydroxyphenyl thiazole,hydroxydiaryl oxadiazole, hydroxydiaryl thiadiazole, hydroxyphenylpyridine, hydroxyphenyl benzoimidazole, hydroxybenzo triazole, hydroxyfluborane, bipyridyl, phenanthroline, phthalocyanine, porphyrin,cyclopentadiene, β-diketones, azomethines, or a derivative thereof, butthe ligand is not limited thereto.

The reductive dopant is preferably added to form a layer or an islandpattern in the interfacial region. The layer of the reductive dopant orthe island pattern of the reductive dopant is preferably formed bydepositing the reductive dopant by resistance heating deposition whilean emitting material for forming the interfacial region or an organicsubstance as a electron-injecting material are simultaneously deposited,so that the reductive dopant is dispersed in the organic substance.Dispersion concentration at which the reductive dopant is dispersed inthe organic substance is a mole ratio (organic substance to reductivedopant) of 100:1 to 1:100, preferably 5:1 to 1:5.

When the reductive dopant forms the layer, the emitting material or theelectron injecting material for forming the organic layer of theinterfacial region is initially layered, and the reductive dopant issubsequently deposited singularly thereon by resistance heatingdeposition to form a preferably 0.1 to 15 nm-thick layer.

When the reductive dopant forms the island pattern, the emittingmaterial or the electron injecting material for forming the organiclayer of the interfacial region is initially formed in an island shape,and the reductive dopant is subsequently deposited singularly thereon byresistance heating deposition to form a preferably 0.05 to 1 nm-thickisland shape.

A ratio of the main component to the reductive dopant in the organic ELdevice according to the present invention is preferably a mole ratio(main component to reductive dopant) of 5:1 to 1:5, more preferably 2:1to 1:2.

The organic EL device according to the present invention preferablyincludes the electron injecting layer between the emitting layer and thecathode, and the electron injecting layer preferably contains anitorogen-containing cyclic derivative as the main component.

It should be noted that “as the main component” means that thenitrogen-containing cyclic derivative is contained in the electroninjecting layer with a content of 50 mass % or more.

The electron injecting layer or the electron transporting layer, whichaids injection of the electrons into the emitting layer, has a highelectron mobility. The electron injecting layer is provided foradjusting energy level, by which, for instance, sudden changes of theenergy level can be reduced.

A preferable example of an electron transporting material for formingthe electron injecting layer is an aromatic heterocyclic compound havingin the molecule at least one heteroatom. Particularly, anitrogen-containing cyclic derivative is preferable.

A preferable example of the nitrogen-containing cyclic derivative is anitrogen-containing cyclic metal chelate complex represented by thefollowing formula (A).

In the formula, R² to R⁷ each independently represent a hydrogen atom, ahalogen atom, an oxy group, an amino group, a hydrocarbon group having 1to 40 carbon atoms, an alkoxy group, an aryloxy group, an alkoxycarbonylgroup or a heterocyclic group. R² to R⁷ may be substituted orunsubstituted.

Examples of the halogen atom are fluorine, chlorine, bromine, iodine andthe like. Examples of a substituted or unsubstituted amino group are analkylamino group, an arylamino group and an aralkylamino group.

Examples of the hydrocarbon group having 1 to 40 carbon atoms are asubstituted or unsubstituted alkyl group, an alkenyl group, a cycloalkylgroup, an aryl group, an aralkyl group and the like.

Examples of the alkyl group are a methyl group, ethyl group, propylgroup, isopropyl group, n-butyl group, s-butyl group, isobutyl group,t-butyl group, n-pentyl group, n-hexyl group, n-heptyl group, n-octylgroup, n-nonyl group, n-decyl group, n-undecyl group, n-dodecyl group,n-tridecyl group, n-tetradecyl group, n-pentadecyl group, n-hexadecylgroup, n-heptadecyl group, n-octadecyl group, neo-pentyl group,1-methylpentyl group, 2-methylpentyl group, 1-pentylhexyl group,1-butylpentyl group, 1-heptyloctyl group, 3-methylpentyl group,hydroxymethyl group, 1-hydroxyethyl group, 2-hydroxyethyl group,2-hydroxyisobutyl group, 1,2-dihydroroxyethyl group,1,3-dihydroxyisopropyl group, 2,3-dihydroxy-t-butyl group,1,2,3-trihydroxypropyl group, chloromethyl group, 1-chloroethyl group,2-chloroethyl group, 2-chloroisobutyl group, 1,2-dichloroethyl group,1,3-dichloroisopropyl group, 2,3-dichloro-t-butyl group,1,2,3-trichloropropyl group, bromomethyl group, 1-bromoethyl group,2-bromoethyl group, 2-bromoisobutyl group, 1,2-dibromoethyl group,1,3-dibromoisopropyl group, 2,3-dibromo-t-butyl group,1,2,3-tribromopropyl group, iodomethyl group, 1-iodoethyl group,2-iodoethyl group, 2-iodoisobutyl group, 1,2-diiodoethyl group,1,3-diiodoisopropyl group, 2,3-diiodo-t-butyl group, 1,2,3-triiodopropylgroup, aminomethyl group, 1-aminoethyl group, 2-aminoethyl group,2-aminoisobutyl group, 1,2-diaminoethyl group, 1,3-diaminoisopropylgroup, 2,3-diamino-t-butyl group, 1,2,3-triaminopropyl group,cyanomethyl group, 1-cyanoethyl group, 2-cyanoethyl group,2-cyanoisobutyl group, 1,2-dicyanoethyl group, 1,3-dicyanoisopropylgroup, 2,3-dicyano-t-butyl group, 1,2,3-tricyanopropyl group,nitromethyl group, 1-nitroethyl group, 2-nitroethyl group,1,2-dinitroethyl group, 2,3-dinitro-t-butyl group and1,2,3-trinitropropyl group.

Among the above, the alkyl group is preferably a methyl group, an ethylgroup, a propyl group, an isopropyl group, an n-butyl group, a s-butylgroup, an isobutyl group, a t-butyl group, an n-pentyl group, an n-hexylgroup, an n-heptyl group, an n-octyl group, an n-nonyl group, an n-decylgroup, an n-undecyl group, an n-dodecyl group, an n-tridecyl group, ann-tetradecyl group, an n-pentadecyl group, an n-hexadecyl group, ann-heptadecyl group, an n-octadecyl group, an neo-pentyl group, a1-methylpentyl group, a 1-pentylhexyl group, a 1-butylpentyl group, or a1-heptyloctyl group.

Examples of the alkenyl group are a vinyl group, allyl group, 1-butenylgroup, 2-butenyl group, 3-butenyl group, 1,3-butanedienyl group,1-methylvinyl group, styryl group, 2,2-diphenylvinyl group,1,2-diphenylvinyl group, 1-methylallyl group, 1,1-dimethylallyl group,2-methylallyl group, 1-phenylallyl group, 2-phenylallyl group,3-phenylallyl group, 3,3-diphenylallyl group, 1,2-dimethylallyl group,1-phenyl-1-butenyl group and 3-phenyl-1-butenyl group, among which astyryl group, 2,2-phenylvinyl group, 1,2-diphenylvinyl group and thelike are preferable.

Examples of the cycloalkyl group are a cyclopentyl group, cyclohexylgroup, cyclooctyl group, and 3,5-tetramethylcyclohexyl group, amongwhich cyclohexyl group, cyclooctyl group and 3,5-tetramethylcyclohexylgroup are preferable.

The alkoxy group is a group represented by —OY. Examples of Y are thesame as the examples described in relation to the alkyl group, andpreferable examples of Y are also the same as those described inrelation to the alkyl group.

Examples of non-condensed aryl group are a phenyl group, biphenyl-2-ylgroup, biphenyl-3-yl group, biphenyl-4-yl group, p-terphenyl-4-yl group,p-terphenyl-3-yl group, p-terphenyl-2-yl group, m-terphenyl-4-yl group,m-terphenyl-3-yl group, m-terphenyl-2-yl group, o-tolyl group, m-tolylgroup, p-tolyl group, p-t-butylphenyl group, p-(2-phenylpropyl)phenylgroup, 4′-methylbiphenylyl group, 4″-t-butyl-p-terphenyl-4-yl group,o-cumenyl group, m-cumenyl group, p-cumenyl group, 2,3-xylyl group,3,4-xylyl group, 2,5-xylyl group, mesityl group, m-quarter-phenyl groupand the like.

Among the above, a phenyl group, a biphenyl-2-yl group, a biphenyl-3-ylgroup, a biphenyl-4-yl group, an m-terphenyl-4-yl group, anm-terphenyl-3-yl group, an m-terphenyl-2-yl group, a p-tolyl group, a3,4-xylyl group, an m-quarter-phenyl-2-yl group are preferable.

Examples of a condensed aryl group are a 1-naphthyl group and 2-naphtylgroup.

The heterocyclic group, which may be monocyclic or condensed, preferablyhas 1 to 20 carbon atoms forming the ring, more preferably 1 to 12carbon atoms forming the ring, further preferably 2 to 10 carbon atomsforming the ring. The heterocyclic group is an aromatic heterocyclicgroup having at least one heteroatom selected from a group of a nitrogenatom, an oxygen atom, a sulfur atom and a selenium atom. Examples of theheterocyclic group are groups induced by pirrolidine, piperidine,piperazine, morpholine, thiophene, selenophene, furane, pyrrole,imidazole, pyrazole, pyridine, pyrazine, pyridazine, pyrimidine,triazole, triazine, indole, indazole, purine, thiazoline, thiazole,thiadiazole, oxazoline, oxazole, oxadiazole, quinoline, isoquinoline,phthalazine, naphthyridine, quinoxaline, quinazoline, cinnoline,pteridine, acridine, phenanthroline, phenazine, tetrazole,benzoimidazole, benzooxazole, benzothiazole, benzotriazole, tetra-azaindene, carbazole, azepine and the like, preferably groups induced byfurane, thiophene, pyridine, pyrazine, pyrimidine, pyridazine, triazine,quinoline, phthalazine, naphthyridine, quinoxaline and quinazoline,further preferably groups induced by frane, thiophene, pyridine andquinoline, further more preferably a quinolinyl group.

Examples of the aralkyl group are a benzyl group, 1-phenylethyl group,2-phenylethyl group, 1-phenylisopropyl group, 2-phenylisopropyl group,phenyl-t-butyl group, α-naphthylmethyl group, 1-α-naphthylethyl group,2-α-naphthylethyl group, 1-α-naphthylisopropyl group,2-α-naphthylisopropyl group, β-naphthylmethyl group, 1-β-naphthylethylgroup, 2-β-naphthylethyl group, 1-β-naphthylisopropyl group,2-β-naphthylisopropyl group, p-methylbenzyl group, m-methylbenzyl group,o-methylbenzyl group, p-chlorobenzyl group, m-chlorobenzyl group,o-chlorobenzyl group, p-bromobenzyl group, m-bromobenzyl group,o-bromobenzyl group, p-iodobenzyl group, m-iodobenzyl group,o-iodobenzyl group, p-hydroxybenzyl group, m-hydroxybenzyl group,o-hydroxybenzyl group, p-aminobenzyl group, m-aminobenzyl group,o-aminobenzyl group, p-nitrob-enzyl group, m-nitrobenzyl group,o-nitrobenzyl group, p-cyanobenzyl group, m-cyanobenzyl group,o-cyanobenzyl group, 1-hydroxy-2-phenylisopropyl group,1-chloro-2-phenylisopropyl group and the like.

Among the above, a benzyl group, p-cyanobenzyl group, m-cyanobenzylgroup, o-cyanobenzyl group, 1-phenylethyl group, 2-phenylethyl group,1-phenylisopropyl group and 2-phenylisopropyl group are preferable.

The aryloxy group is represented by —OY′. Preferable examples of Y′ area phenyl group, 1-naphthyl group, 2-naphthyl group, 1-anthryl group,2-anthryl group, 9-anthryl group, 1-phenanthryl group, 2-phenanthrylgroup, 3-phenanthryl group, 4-phenanthryl group, 9-phenanthryl group,1-naphthacenyl group, 2-naphthacenyl group, 9-naphthacenyl group,1-pyrenyl group, 2-pyrenyl group, 4-pyrenyl group, 2-biphenylyl group,3-biphenylyl group, 4-biphenylyl group, p-terphenyl-4-yl group,p-terphenyl-3-yl group, p-terphenyl-2-yl group, m-terphenyl-4-yl group,m-terphenyl-3-yl group, m-terphenyl-2-yl group, o-tolyl group, m-tolylgroup, p-tolyl group, p-t-butylphenyl group, p-(2-phenylpropyl)phenylgroup, 3-methyl-2-naphthyl group, 4-methyl-1-naphthyl group,4-methyl-1-anthryl group, 4′-methylbiphenylyl group,4″-t-butyl-p-terphenyl-4-yl group and the like.

A heteroaryloxy group of the aryloxy group is represented by —OZ′.Examples of Z′ are a 2-pyroryl group, 3-pyroryl group, pyrazinyl group,2-pyridinyl group, 3-pyridinyl group, 4-pyridinyl group, 2-indolylgroup, 3-indolyl group, 4-indolyl group, 5-indolyl group, 6-indolylgroup, 7-indolyl group, 1-isoindolyl group, 3-isoindolyl group,4-isoindolyl group, 5-isoindolyl group, 6-isoindolyl group, 7-isoindolylgroup, 2-furyl group, 3-furyl group, 2-benzofuranyl group,3-benzofuranyl group, 4-benzofuranyl group, 5-benzofuranyl group,6-benzofuranyl group, 7-benzofuranyl group, 1-isobenzofuranyl group,3-isobenzofuranyl group, 4-isobenzofuranyl group, 5-isobenzofuranylgroup, 6-isobenzofuranyl group, 7-isobenzofuranyl group, 2-quinolylgroup, 3-quinolyl group, 4-quinolyl group, 5-quinolyl group, 6-quinolylgroup, 7-quinolyl group, 8-quinolyl group, 1-isoquinolyl group,3-isoquinolyl group, 4-isoquinolyl group, 5-isoquinolyl group,6-isoquinolyl group, 7-isoquinolyl group, 8-isoquinolyl group,2-quinoxalinyl group, 5-quinoxalinyl group, 6-quinoxalinyl group,1-carbazolyl group, 2-carbazolyl group, 3-carbazolyl group, 4-carbazolylgroup, 1-phenanthrydinyl group, 2-phenanthrydinyl group,3-phenanthrydinyl group, 4-phenanthrydinyl group, 6-phenanthrydinylgroup, 7-phenanthrydinyl group, 8-phenanthrydinyl group,9-phenanthrydinyl group, 10-phenanthrydinyl group, 1-acridinyl group,2-acridinyl group, 3-acridinyl group, 4-acridinyl group, 9-acridinylgroup, 1,7-phenanthroline-2-yl group, 1,7-phenanthroline-3-yl group,1,7-phenanthroline-4-yl group, 1,7-phenanthroline-5-yl group,1,7-phenanthroline-6-yl group, 1,7-phenanthroline-8-yl group,1,7-phenanthroline-9-yl group, 1,7-phenanthroline-10-yl group,1,8-phenanthroline-2-yl group, 1,8-phenanthroline-3-yl group,1,8-phenanthroline-4-yl group, 1,8-phenanthroline-5-yl group,1,8-phenanthroline-6-yl group, 1,8-phenanthroline-7-yl group,1,8-phenanthroline-9-yl group, 1,8-phenanthroline-10-yl group,1,9-phenanthroline-2-yl group, 1,9-phenanthroline-3-yl group,1,9-phenanthroline-4-yl group, 1,9-phenanthroline-5-yl group,1,9-phenanthroline-6-yl group, 1,9-phenanthroline-7-yl group,1,9-phenanthroline-8-yl group, 1,9-phenanthroline-10-yl group,1,10-phenanthroline-2-yl group, 1,10-phenanthroline-3-yl group,1,10-phenanthroline-4-yl group, 1,10-phenanthroline-5-yl group,2,9-phenanthroline-1-yl group, 2,9-phenanthroline-3-yl group,2,9-phenanthroline-4-yl group, 2,9-phenanthroline-5-yl group,2,9-phenanthroline-6-yl group, 2,9-phenanthroline-7-yl group,2,9-phenanthroline-8-yl group, 2,9-phenanthroline-10-yl group,2,8-phenanthroline-1-yl group, 2,8-phenanthroline-3-yl group,2,8-phenanthroline-4-yl group, 2,8-phenanthroline-5-yl group,2,8-phenanthroline-6-yl group, 2,8-phenanthroline-7-yl group,2,8-phenanthroline-9-yl group, 2,8-phenanthroline-10-yl group,2,7-phenanthroline-1-yl group, 2,7-phenanthroline-3-yl group,2,7-phenanthroline-4-yl group, 2,7-phenanthroline-5-yl group,2,7-phenanthroline-6-yl group, 2,7-phenanthroline-8-yl group,2,7-phenanthroline-9-yl group, 2,7-phenanthroline-10-yl group,1-phenazinyl group, 2-phenazinyl group, 1-phenothiazinyl group,2-phenothiazinyl group, 3-phenothiazinyl group, 4-phenothiazinyl group,1-phenoxazinyl group, 2-phenoxazinyl group, 3-phenoxazinyl group,4-phenoxazinyl group, 2-oxazolyl group, 4-oxazolyl group, 5-oxazolylgroup, 2-oxadiazolyl group, 5-oxadiazolyl group, 3-furazanyl group,2-thienyl group, 3-thienyl group, 2-methylpyrrole-1-yl group,2-methylpyrrole-3-yl group, 2-methylpyrrole-4-yl group,2-methylpyrrole-5-yl group, 3-methylpyrrole-1-yl group,3-methylpyrrole-2-yl group, 3-methylpyrrole-4-yl group,3-methylpyrrole-5-yl group, 2-t-butylpyrrole-3-yl group,3-(2-phenylpropyl)pyrrole-1-yl group, 2-methyl-1-indolyl group,4-methyl-1-indolyl group, 2-methyl-3-indolyl group, 4-methyl-3-indolylgroup, 2-t-butyl-1-indolyl group, 4-t-butyl-1-indolyl group,2-t-butyl-3-indolyl group, 4-t-butyl-3-indolyl group and the like.

The alkoxycarbonyl group is represented by —COOY′. Examples of Y′ arethe same as the examples of the alkyl group.

The alkylamino group and the aralkylamino group are represented by—NQ¹Q². Examples for each of Q¹ and Q² are the same as the examplesdescribed in relation to the alkyl group and the aralkyl group, andpreferable examples for each of Q¹ and Q² are also the same as thosedescribed in relation to the alkyl group and the aralkyl group. Eitherone of Q¹ and Q² may be a hydrogen atom.

The arylamino group is represented by —NAr¹Ar². Examples for each of Ar¹and Ar² are the same as the examples described in relation to thenon-condensed aryl group and the condensed aryl group. Either one of Ar¹and Ar² may be a hydrogen atom.

M represents aluminum (Al), gallium (Ga) or indium (In), among which Inis preferable.

L in the formula (A) represents a group represented by the followingformula (A′) or the following formula (A″).

In the formula, R⁸ to R¹² each independently represent a hydrogen atomor a substituted or unsubstituted hydrocarbon group having 1 to 40carbon atoms. Adjacent groups may form a cyclic structure. R¹³ to R²⁷each independently represent a hydrogen atom or a substituted orunsubstituted hydrocarbon group having 1 to 40 carbon atoms. Adjacentgroups may form a cyclic structure.

Examples of the hydrocarbon group having 1 to 40 carbon atomsrepresented by each of R⁸ to R¹² and R¹³ to R²⁷ in the formulae (A′) and(A″) are the same as those of R² to R⁷.

Examples of a divalent group formed when an adjacent set of R⁸ to R¹²and R¹³ to R²⁷ forms a cyclic structure are a tetramethylene group, apentamethylene group, a hexamethylene group, a diphenylmethane-2,2′-diylgroup, a diphenylethane-3,3′-diyl group, a diphenylpropane-4,4′-diylgroup and the like.

Examples of the nitrogen-containing cyclic metal chelate complexrepresented by the formula (A) will be shown below. However, thenitrogen-containing cyclic metal chelate complex is not limited to theexemplary compounds shown below.

According to the present invention, the electron injecting layerpreferably contains a nitrogen-containing heterocyclic derivative.

The electron injecting layer or the electron transporting layer, whichaids injection of the electrons into the emitting layer, has a highelectron mobility. The electron injecting layer is provided foradjusting energy level, by which, for instance, sudden changes of theenergy level can be reduced. As a material for the electron injectinglayer or the electron transporting layer, 8-hydroxyquinoline or a metalcomplex of its derivative, an oxadiazole derivative and anitrogen-containing heterocyclic derivative are preferable. An exampleof the 8-hydroxyquinoline or the metal complex of its derivative is ametal chelate oxinoid compound containing a chelate of oxine (typically8-quinolinol or 8-hydroxyquinoline). For instance, tris(8-quinolinol)aluminum can be used. Examples of the oxadiazole derivative are asfollows.

In the formula, Ar¹⁷, Ar¹⁸, Ar¹⁹, Ar²¹, Ar²² and Ar²⁵ each represent asubstituted or unsubstituted aryl group. Ar¹⁷, Ar¹⁹ and Ar²² may berespectively the same as or different from Ar¹⁸, Ar²¹ and Ar²⁵. Ar²⁰,Ar²³ and Ar²⁴ each represent a substituted or unsubstituted arylenegroup. Ar²³ and Ar²⁴ may be mutually the same or different.

Examples of the arylene group are a phenylene group, a naphtylene group,a biphenylene group, an anthranylene group, a perylenylene group and apyrenylene group. Examples of the substituent therefor are an alkylgroup having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbonatoms and a cyano group. Such an electron transport compound ispreferably an electron transport compound that can be favorably formedinto a thin film(s). Examples of the electron transport compounds are asfollows.

An example of the nitrogen-containing heterocyclic derivative is anitrogen-containing heterocyclic derivative that is not a metal complex,the derivative being formed of an organic compound represented by eitherone of the following general formulae. Specific examples of thenitrogen-containing heterocyclic derivative are five-membered ring orsix-membered ring derivative having a skeleton represented by theformula (A) and a derivative having a structure represented by theformula (B).

In the formula (B), X represents a carbon atom or a nitrogen atom. Z₁and Z₂ each independently represent an atom group from which anitrogen-containing heterocycle can be formed.

Preferably, the nitrogen-containing heterocyclic derivative is anorganic compound having a nitrogen-containing aromatic polycyclic grouphaving a five-membered ring or six-membered ring. When thenitrogen-containing heterocyclic derivative is such anitrogen-containing aromatic polycyclic group that contains pluralnitrogen atoms, the nitrogen-containing heterocyclic derivative may be anitrogen-containing aromatic polycyclic organic compound having askeleton formed by a combination of the skeletons respectivelyrepresented by the formulae (A) and (B), or by a combination of theskeletons respectively represented by the formulae (A) and (C).

A nitrogen-containing group of the nitrogen-containing organic compoundare selected from nitrogen-containing heterocyclic groups respectivelyrepresented by the following general formulae.

In the formulae: R represents an aryl group having 6 to 40 carbon atoms,a heteroaryl group having 3 to 40 carbon atoms, an alkyl group having 1to 20 carbon atoms or an alkoxy group having 1 to 20 carbon atoms; and nrepresents an integer in a range of 0 to 5. When n is an integer of 2 ormore, plural R may be mutually the same or different.

A preferable specific compound is a nitrogen-containing heterocyclicderivative represented by the following formula.

HAr-L¹-Ar¹—Ar²

In the formula, HAr represents a substituted or unsubstitutednitrogen-containing heterocycle having 3 to 40 carbon atoms; L¹represents a single bond, a substituted or unsubstituted arylene grouphaving 6 to 40 carbon atoms, or a substituted or unsubstitutedheteroarylene group having 3 to 40 carbon atoms; Ar¹ represents asubstituted or unsubstituted divalent aromatic hydrocarbon group having6 to 40 carbon atoms; and Ar² represents a substituted or unsubstitutedaryl group having 6 to 40 carbon atoms, or a substituted orunsubstituted heteroaryl group having 3 to 40 carbon atoms.

HAr is exemplarily selected from the following group.

L¹ is exemplarily selected from the following group.

Ar² is exemplarily selected from the following group.

Ar¹ is exemplarily selected from the following arylanthranil groups.

In the formula, R¹ to R¹⁴ each independently represent a hydrogen atom,a halogen atom, an alkyl group having 1 to 20 carbon atoms, an alkoxygroup having 1 to 20 carbon atoms, an aryloxy group having 6 to 40carbon atoms, a substituted or unsubstituted aryl group having 6 to 40carbon atoms, or a heteroaryl group having 3 to 40 carbon atoms. Ar³represents a substituted or unsubstituted aryl group having 6 to 40carbon atoms, or a heteroaryl group having 3 to 40 carbon atoms.

The nitrogen-containing heterocyclic derivative may be anitrogen-containing heterocyclic derivative in which R¹ to R⁸ in Ar¹represented by the above formula each represent a hydrogen atom.

Other than the above, the following compound (see JP-A-9-3448) can befavorably used.

In the formula, R¹ to R⁴ each independently represent a hydrogen atom, asubstituted or unsubstituted aliphatic group, a substituted orunsubstituted aliphatic cyclic group, a substituted or unsubstitutedcarbocyclic aromatic cyclic group, substituted or unsubstitutedheterocyclic group. X¹ and X² each independently represent an oxygenatom, a sulfur atom or a dicyanomethylene group.

Alternatively, the following compound (see JP-A-2000-173774) can also befavorably used.

In the formula, R¹, R², R³ and R⁴, which may be mutually the same ordifferent, each are represented by the following formula.

In the formula, R⁵, R⁶, R⁷, R⁸ and R⁹, which may be mutually the same ordifferent, each represent a hydrogen atom, a saturated or unsaturatedalkoxy group, an alkyl group, an amino group or an alkylamino group. Atleast one of R⁵, R⁶, R⁷, R⁸ and R⁹ represents a saturated or unsaturatedalkoxy group, an alkyl group, an amino group or an alkylamino group.

A polymer compound containing the nitrogen-containing heterocyclic groupor a nitrogen-containing heterocyclic derivative may be used.

The electron transporting layer preferably contains at least one ofnitrogen-containing heterocycle derivatives respectively represented bythe following formulae (201) to (203).

In the formulae (201) to (203): R represents a hydrogen atom, asubstituted or unsubstituted aryl group having 6 to 60 carbon atoms, asubstituted or unsubstituted pyridyl group, a substituted orunsubstituted quinolyl group, a substituted or unsubstituted alkyl grouphaving 1 to 20 carbon atoms, or a substituted or unsubstituted alkoxygroup having 1 to 20 carbon atoms; n represents an integer in a range of0 to 4; R¹ represents a substituted or unsubstituted aryl group having 6to 60 carbon atoms, a substituted or unsubstituted pyridyl group, asubstituted or unsubstituted quinolyl group, a substituted orunsubstituted alkyl group having 1 to 20 carbon atoms, or an alkoxygroup having 1 to 20 carbon atoms; R² and R³ each independentlyrepresent a hydrogen atom, a substituted or unsubstituted aryl grouphaving 6 to 60 carbon atoms, a substituted or unsubstituted pyrydylgroup, a substituted or unsubstituted quinolyl group, a substituted orunsubstituted alkyl group having 1 to 20 carbon atoms, or a substitutedor unsubstituted alkoxy group having 1 to 20 carbon atoms; L representsa substituted or unsubstituted arylene group having 6 to 60 carbonatoms, a substitutted or unsubstituted pyridinylene group, a substitutedor unsubstituted quinolinylene group, or a substituted or unsubstitutedfluorenylene group; Ar¹ represents a substituted or unsubstitutedarylene group having 6 to 60 carbon atoms, a substituted orunsubstituted pyridinylene group, or a substituted or unsubstitutedquinolinylene group; and Ar² represents a substituted or unsubstitutedaryl group having 6 to 60 carbon atoms, a substituted or unsubstitutedpyridyl group, a substituted or unsubstituted quinolyl group, asubstituted or unsubstituted alkyl group having 1 to 20 carbon atoms ora substituted or unsubstituted alkoxy group having 1 to 20 carbon atoms.

Ar³ represents a substituted or unsubstituted aryl group having 6 to 60carbon atoms, a substituted or unsubstituted pyridyl group, asubstituted or unsubstituted quinolyl group, a substituted orunsubstituted alkyl group having 1 to 20 carbon atoms, a substituted orunsubstituted alkoxy group having 1 to 20 carbon atoms, or a grouprepresented by —Ar¹—Ar² (Ar¹ and Ar² may be the same as the above).

In the formulae (201) to (203), R represents a hydrogen atom, asubstituted or unsubstituted aryl group having 6 to 60 carbon atoms, asubstituted or unsubstituted pyridyl group, substituted or unsubstitutedquinolyl group, a substituted or unsubstituted alkyl group having 1 to20 carbon atoms, or a substituted or unsubstituted alkoxy group having 1to 20 carbon atoms.

The aryl group having 6 to 60 carbon atom is preferably an aryl grouphaving 6 to 40 carbon atoms, more preferably an aryl group having 6 to20 carbon atoms. Examples of such an aryl group are a phenyl group,naphthyl group, anthryl group, phenanthryl group, naphthacenyl group,chrysenyl group, pyrenyl group, biphenyl group, terphenyl group, tolylgroup, t-butylphenyl group, (2-phenylpropyl)phenyl group, fluoranthenylgroup, fluorenyl group, a monovalent group formed of spirobifluorene,perfluorophenyl group, perfluoronaphthyl group, perfluoroanthryl group,perfluorobiphenyl group, a monovalent group formed of9-phenylanthracene, a monovalent group formed of 9-(1′naphthyl)anthracene, a monovalent group formed of 9-(2′-naphthyl) anthracene, amonovalent group formed of 6-phenylchrysene, and a monovalent groupformed of 9-[4-(diphenylamine) phenyl]anthracene, among which a phenylgroup, naphthyl group, biphenyl group, terphenyl group, 9-(10-phenyl)anthryl group, 9-[10-(1′-naphthyl)]anthryl group and9-[10-(2′-naphthyl)]anthryl group are preferable.

The alkyl group having 1 to 20 carbon atoms is preferably an alkyl grouphaving 1 to 6 carbon atoms. Examples of such an alkyl group are a methylgroup, ethyl group, propyl group, butyl group, pentyl group, hexylgroup, and a haloalkyl group such as trifluoromethyl group. When such analkyl group has 3 or more carbon atoms, the alkyl group may be linear,cyclic or branched.

The alkoxy group having 1 to 20 carbon atoms is preferably an alkoxygroup having 1 to 6 carbon atoms. Examples of such an alkoxy group are amethoxy group, ethoxy group, propoxy group, butoxy group, pentyloxygroup, and hexyloxy group. When such an alkoxy group has 3 or morecarbon atoms, the alkoxy group may be linear, cyclic or branched.

Examples of a substituent for the group represented by R are a halogenatom, a substituted or unsubstituted alkyl group having 1 to 20 carbonatoms, a substituted or unsubstituted alkoxy group having 1 to 20 carbonatoms, a substituted or unsubstituted aryloxy group having 6 to 40carbon atoms, a substituted or unsubstituted aryl group having 6 to 40carbon atoms, or a substituted or unsubstituted heteroaryl group having3 to 40 carbon atoms.

Examples of the halogen atom are fluorine, chlorine, bromine, iodine andthe like.

Examples for each of the alkyl group having 1 to 20 carbon atoms, thealkoxy group having 1 to 20 carbon atoms, and an aryl group having 6 to40 carbon atoms may be the same as the above examples.

Examples of the aryloxy group having 6 to 40 carbon atoms are a phenoxygroup and a biphenyloxy group.

Examples of the heteroaryl group having 3 to 40 carbon atoms are apyroryl group, furyl group, thienyl group, silolyl group, pyridyl group,quinolyl group, isoquinolyl group, benzofuryl group, imidazolyl group,pyrimidyl group, carbazolyl group, selenophenyl group, oxadiazolyl groupand triazolyl group.

n is an integer in a range of 0 to 4, preferably 0 to 2.

In the formulae (201), R¹ represents a substituted or unsubstituted arylgroup having 6 to 60 carbon atoms, a substituted or unsubstitutedpyridyl group, substituted or unsubstituted quinolyl group, asubstituted or unsubstituted alkyl group having 1 to 20 carbon atoms, oran alkoxy group having 1 to 20 carbon atoms.

Examples for each of the groups, the preferable number of carbon atomscontained in each of the groups, and preferable examples of thesubstituent for each of the groups are the same as those described inrelation to R.

In the formulae (202) and (203), R² and R³ each independently representa hydrogen atom, a substituted or unsubstituted aryl group having 6 to60 carbon atoms, a substituted or unsubstituted pyridyl group,substituted or unsubstituted quinolyl group, a substituted orunsubstituted alkyl group having 1 to 20 carbon atoms, or a substitutedor unsubstituted alkoxy group having 1 to 20 carbon atoms.

Examples for each of the groups, the preferable number of carbon atomscontained in each of the groups, and preferable examples of thesubstituent for each of the groups are the same as those described inrelation to R.

In the formulae (201) to (203), L represents a substituted orunsubstituted arylene group having 6 to 60 carbon atoms, a substitutedor unsubstituted pyridinylene group, a substituted or unsubstitutedquinolinylene group, or a substituted or unsubstituted fluorenylenegroup.

The arylene group having 6 to 60 carbon atoms is preferably an arylenegroup having 6 to 40 carbon atoms, more preferably an arylene grouphaving 6 to 20 carbon atoms. An example of such an arylene group is adivalent group formed by removing one hydrogen atom from the aryl grouphaving been described in relation to R. Examples of a substituent forthe group represented by L are the same as those described in relationto R.

Alternatively, L is preferably a group selected from a group consistingof the following.

In the formulae (201), Ar¹ represents a substituted or unsubstitutedarylene group having 6 to 60 carbon atoms, a substituted orunsubstituted pyridinylene group, or a substituted or unsubstitutedquinolinylene group. Examples of a substituent for the groupsrespectively represented by Ar¹ and Ar³ are the same as those describedin relation to R.

Alternatively, Ar¹ is preferably selected from a group consisting ofcondensed cyclic groups respectively represented by the followingformulae (101) to (110).

In the formulae (101) to (110), the condensed rings each may be linkedwith a link group formed of a halogen atom, a substituted orunsubstituted alkyl group having 1 to 20 carbon atoms, a substituted orunsubstituted alkoxy group having 1 to 20 carbon atoms, a substituted orunsubstituted aryloxy group having 6 to 40 carbon atoms, a substitutedor unsubstituted aryl group having 6 to 40 carbon atoms or a substitutedor unsubstituted heteroaryl group having 3 to 40 carbon atoms. When therings each is linked with plural link groups, the plural link groups maybe mutually the same or different. Examples for each of the groups arethe same as those described above.

In the formula (110), L′ represents a single bond or a group selectedfrom a group consisting of the following.

The structure of Ar¹ represented by the formula (103) is preferably acondensed cyclic group represented by any one of the following formulae(111) to (125).

In the formulae (111) to (125), the condensed rings each may be linkedwith a link group formed of a halogen atom, a substituted orunsubstituted alkyl group having 1 to 20 carbon atoms, a substituted orunsubstituted alkoxy group having 1 to 20 carbon atoms, a substituted orunsubstituted aryloxy group having 6 to 40 carbon atoms, a substitutedor unsubstituted aryl group having 6 to 40 carbon atoms or a substitutedor unsubstituted heteroaryl group having 3 to 40 carbon atoms. When therings each is linked with plural link groups, the plural link groups maybe mutually the same or different. Examples for each of the groups arethe same as those described above.

In the formula (201), Ar² represents a substituted or unsubstituted arylgroup having 6 to 60 carbon atoms, a substituted or unsubstitutedpyridyl group, substituted or unsubstituted quinolyl group, asubstituted or unsubstituted alkyl group having 1 to 20 carbon atoms, ora substituted or unsubstituted alkoxy group having 1 to 20 carbon atoms.

Examples for each of the groups, the preferable number of carbon atomscontained in each of the groups, and preferable examples of thesubstituent for each of the groups are the same as those described inrelation to R.

In the formulae (202) and (203), Ar³ represents a substituted orunsubstituted aryl group having 6 to 60 carbon atoms, a substituted orunsubstituted pyridyl group, a substituted or unsubstituted quinolylgroup, a substituted or unsubstituted alkyl group having 1 to 20 carbonatoms, a substituted or unsubstituted alkoxy group having 1 to 20 carbonatoms, or a group represented by —Ar¹—Ar² (Ar¹ and Ar² may be the sameas the above).

Examples for each of the groups, the preferable number of carbon atomscontained in each of the groups, and preferable examples of thesubstituent for each of the groups are the same as those described inrelation to R.

Alternatively, Ar³ is preferably selected from a group consisting ofcondensed cyclic groups respectively represented by the followingformulae (126) to (135).

In the formulae (126) to (135), the condensed rings each may be linkedwith a link group formed of a halogen atom, a substituted orunsubstituted alkyl group having 1 to 20 carbon atoms, a substituted orunsubstituted alkoxy group having 1 to 20 carbon atoms, a substituted orunsubstituted aryloxy group having 6 to 40 carbon atoms, a substitutedor unsubstituted aryl group having 6 to 40 carbon atoms or a substitutedor unsubstituted heteroaryl group having 3 to 40 carbon atoms. When therings each is linked with plural link groups, the plural link groups maybe mutually the same or different. Examples for each of the groups arethe same as those described above.

In the formula (135), L′ represents the same as the above.

In the formulae (126) to (135), R′ represents a hydrogen atom, asubstituted or unsubstituted alkyl group having 1 to 20 carbon atoms, asubstituted or unsubstituted aryl group having 6 to 40 carbon atoms, orsubstituted or unsubstituted heteroaryl group having 3 to 40 carbonatoms. Examples for each of the groups are the same as those describedabove.

A structure represented by the formula (128), which is an example ofAr³, is preferably a condensed cyclic group represented by any one ofthe following formulae (136) to (158).

In the formulae (136) to (158), the condensed rings each may be linkedwith a link group formed of a halogen atom, a substituted orunsubstituted alkyl group having 1 to 20 carbon atoms, a substituted orunsubstituted alkoxy group having 1 to 20 carbon atoms, a substituted orunsubstituted aryloxy group having 6 to 40 carbon atoms, a substitutedor unsubstituted aryl group having 6 to 40 carbon atoms or a substitutedor unsubstituted heteroaryl group having 3 to 40 carbon atoms. When therings each is linked with plural link groups, the plural link groups maybe mutually the same or different. Examples for each of the groups arethe same as those described above. R′ is the same as the above.

Alternatively, Ar² and Ar³ each independently are preferably a groupselected from a group consisting of the following.

Examples of the nitrogen-containing heterocyclic derivative representedby any one of the general formulae (201) to (203) according to thepresent invention will be shown below. However, the present invention isnot limited to the exemplary compounds shown below.

In the chart shown below, HAr represents any one of structuresrepresented by the formulae (201) to (203).

HAr—L—Ar¹—Ar² HAr L Ar¹ Ar² 1-1

2

3

4

5

6

7

8

9

10

11

12

13

14

2-1

2

3

4

5

6

7

8

9

3-1

2

3

4

5

6

4-1

2

3

4

5

6

7

8

9

10

11

12

5-1

2

3

4

5

6

6-1

2

3

4

5

7-1

2

3

4

5

6

7

8

9

10

8-1

2

3

4

5

6

7

8

9

10

11

12

13

9-1

2

3

4

5

6

7

8

9

10

11

12

13

14

10-1

2

3

4

5

6

7

8

9

11-1

2

3

4

5

6

12-1

2

3

4

5

6

7

8

9

10

11

13-1

2

3

4

5

6

14-1

2

3

4

5

15-1

2

3

4

5

6

7

8

9

10

16-1

2

3

4

5

6

7

8

17-1

2

3

4

5

6

7

8

Among the above examples, examples (1-1), (1-5), (1-7), (2-1), (3-1),(4-2), (4-6), (7-2), (7-7), (7-8), (7-9), (9-1) and (9-7) areparticularly preferred.

Although thickness of the electron injecting layer or the electrontransporting layer is not specifically limited, the thickness ispreferably 1 to 100 nm.

The electron injecting layer preferably contains an inorganic compoundsuch as an insulator or a semiconductor in addition to thenitrogen-containing cyclic derivative. Such an insulator or asemiconductor, when contained in the electron injecting layer, caneffectively prevent a current leak, thereby enhancing electroninjectability of the electron injecting layer.

As the insulator, it is preferable to use at least one metal compoundselected from a group consisting of an alkali metal chalcogenide, analkali earth metal chalcogenide, a halogenide of alkali metal and ahalogenide of alkali earth metal. By forming the electron injectinglayer from the alkali metal chalcogenide or the like, the electroninjecting capability can preferably be further enhanced. Specifically,preferable examples of the alkali metal chalcogenide are Li₂O, K₂O,Na₂S, Na₂Se and Na₂O, while preferable example of the alkali earth metalchalcogenide are CaO, BaO, SrO, BeO, BaS and CaSe. Preferable examplesof the halogenide of the alkali metal are LiF, NaF, KF, LiCl, KCl andNaCl. Preferable examples of the halogenide of the alkali earth metalare fluorides such as CaF₂, BaF₂, SrF₂, MgF₂ and BeF₂, and halogenidesother than the fluoride.

Examples of the semiconductor are one of or a combination of two or moreof an oxide, a nitride or an oxidized nitride containing at least oneelement selected from a group consisting of Ba, Ca, Sr, Yb, Al, Ga, In,Li, Na, Cd, Mg, Si, Ta, Sb and Zn. The inorganic compound for formingthe electron injecting layer is preferably a microcrystalline oramorphous insulator film. When the electron injecting layer is formed ofsuch insulator film, more uniform thin film can be formed, therebyreducing pixel defects such as a dark spot. Examples of such aninorganic compound are the above-described alkali metal chalcogenide,alkali earth metal chalcogenide, halogenide of the alkali metal andhalogenide of the alkali earth metal.

The electron injecting layer according to the present invention maypreferably contain the above-described reductive dopant.

The hole injecting layer or the hole transporting layer (including thehole injecting/transporting layer) may contain an aromatic aminecompound such as an aromatic amine derivative represented by thefollowing general formula (I).

In the above formula (I), Ar¹ to Ar⁴ each represent a substituted orunsubstituted aryl group having 6 to 50 carbon atoms forming a ring or asubstituted or unsubstituted heteroaryl group having 5 to 50 atomsforming a ring.

Examples of the substituted or unsubstituted aryl group having 6 to 50ring carbon atoms are a phenyl group, 1-naphthyl group, 2-naphthylgroup, 1-anthryl group, 2-anthryl group, 9-anthryl group, 1-phenanthrylgroup, 2-phenanthryl group, 3-phenanthryl group, 4-phenanthryl group,9-phenanthryl group, 1-naphthacenyl group, 2-naphthacenyl group,9-naphthacenyl group, 1-pyrenyl group, 2-pyrenyl group, 4-pyrenyl group,2-biphenylyl group, 3-biphenylyl group, 4-biphenylyl group,p-terphenyl-4-yl group, p-terphenyl-3-yl group, p-terphenyl-2-yl group,m-terphenyl-4-yl group, m-terphenyl-3-yl group, m-terphenyl-2-yl group,o-tolyl group, m-tolyl group, p-tolyl group, p-t-butylphenyl group,p-(2-phenylpropyl)phenyl group, 3-methyl-2-naphthyl group,4-methyl-1-naphthyl group, 4-methyl-1-anthryl group, 4′-methylbiphenylylgroup, 4″-t-butyl-p-terphenyl-4-yl group, fluoranthenyl group, fluorenylgroup and the like.

Examples of the substituted or unsubstituted heteroaryl group having 5to 50 ring atoms are a 1-pyroryl group, 2-pyroryl group, 3-pyrorylgroup, pyrazinyl group, 2-pyridiny group, 3-pyridinyl group, 4-pyridinylgroup, 1-indolyl group, 2-indolyl group, 3-indolyl group, 4-indolylgroup, 5-indolyl group, 6-indolyl group, 7-indolyl group, 1-isoindolylgroup, 2-isoindolyl group, 3-isoindolyl group, 4-isoindolyl group,5-isoindolyl group, 6-isoindolyl group, 7-isoindolyl group, 2-furylgroup, 3-furyl group, 2-benzofuranyl group, 3-benzofuranyl group,4-benzofuranyl group, 5-benzofuranyl group, 6-benzofuranyl group,7-benzofuranyl group, 1-isobenzofuranyl group, 3-isobenzofuranyl group,4-isobenzofuranyl group, 5-isobenzofuranyl group, 6-isobenzofuranylgroup, 7-isobenzofuranyl group, quinolyl group, 3-quinolyl group,4-quinolyl group, 5-quinolyl group, 6-quinolyl group, 7-quinolyl group,8-quinolyl group, 1-isoquinolyl group, 3-isoquinolyl group,4-isoquinolyl group, 5-isoquinolyl group, 6-isoquinolyl group,7-isoquinolyl group, 8-isoquinolyl group, 2-quinoxalinyl group,5-quinoxalinyl group, 6-quinoxalinyl group, 1-carbazolyl group,2-carbazolyl group, 3-carbazolyl group, 4-carbazolyl group, 9-carbazolylgroup, 1-phenanthrydinyl group, 2-phenanthrydinyl group,3-phenanthrydinyl group, 4-phenanthrydinyl group, 6-phenanthrydinylgroup, 7-phenanthrydinyl group, 8-phenanthrydinyl group,9-phenanthrydinyl group, 10-phenanthrydinyl group, 1-acridinyl group,2-acridinyl group, 3-acridinyl group, 4-acridinyl group, 9-acridinylgroup, 1,7-phenanthroline-2-yl group, 1,7-phenanthroline-3-yl group,1,7-phenanthroline-4-yl group, 1,7-phenanthroline-5-yl group,1,7-phenanthroline-6-yl group, 1,7-phenanthroline-8-yl group,1,7-phenanthroline-9-yl group, 1,7-phenanthroline-10-yl group,1,8-phenanthroline-2-yl group, 1,8-phenanthroline-3-yl group,1,8-phenanthroline-4-yl group, 1,8-phenanthroline-5-yl group,1,8-phenanthroline-6-yl group, 1,8-phenanthroline-7-yl group,1,8-phenanthroline-9-yl group, 1,8-phenanthroline-10-yl group,1,9-phenanthroline-2-yl group, 1,9-phenanthroline-3-yl group,1,9-phenanthroline-4-yl group, 1,9-phenanthroline-5-yl group,1,9-phenanthroline-6-yl group, 1,9-phenanthroline-7-yl group,1,9-phenanthroline-8-yl group, 1,9-phenanthroline-10-yl group,1,10-phenanthroline-2-yl group, 1,10-phenanthroline-3-yl group,1,10-phenanthroline-4-yl group, 1,10-phenanthroline-5-yl group,2,9-phenanthroline-1-yl group, 2,9-phenanthroline-3-yl group,2,9-phenanthroline-4-yl group, 2,9-phenanthroline-5-yl group,2,9-phenanthroline-6-yl group, 2,9-phenanthroline-7-yl group,2,9-phenanthroline-8-yl group, 2,9-phenanthroline-10-yl group,2,8-phenanthroline-1-yl group, 2,8-phenanthroline-3-yl group,2,8-phenanthroline-4-yl group, 2,8-phenanthroline-5-yl group,2,8-phenanthroline-6-yl group, 2,8-phenanthroline-7-yl group,2,8-phenanthroline-9-yl group, 2,8-phenanthroline-10-yl group,2,7-phenanthroline-1-yl group, 2,7-phenanthroline-3-yl group,2,7-phenanthroline-4-yl group, 2,7-phenanthroline-5-yl group,2,7-phenanthroline-6-yl group, 2,7-phenanthroline-8-yl group,2,7-phenanthroline-9-yl group, 2,7-phenanthroline-10-yl group,1-phenazinyl group, 2-phenazinyl group, 1-phenothiazinyl group,2-phenothiazinyl group, 3-phenothiazinyl group, 4-phenothiazinyl group,10-phenothiazinyl group, 1-phenoxazinyl group, 2-phenoxazinyl group,3-phenoxazinyl group, 4-phenoxazinyl group, 10-phenoxazinyl group,2-oxazolyl group, 4-oxazolyl group, 5-oxazolyl group, 2-oxadiazolylgroup, 5-oxadiazolyl group, 3-furazanyl group, 2-thienyl group,3-thienyl group, 2-methylpyrrole-1-yl group, 2-methylpyrrole-3-yl group,2-methylpyrrole-4-yl group, 2-methylpyrrole-5-yl group,3-methylpyrrole-1-yl group, 3-methylpyrrole-2-yl group,3-methylpyrrole-4-yl group, 3-methylpyrrole-5-yl group,2-t-butylpyrrole-3-yl group, 3-(2-phenylpropyl)pyrrole-1-yl group,2-methyl-1-indolyl group, 4-methyl-1-indolyl group, 2-methyl-3-indolylgroup, 4-methyl-3-indolyl group, 2-t-butyl-1-indolyl group,4-t-butyl-1-indolyl group, 2-t-butyl-3-indolyl group,4-t-butyl-3-indolyl group and the like. Among the above, a phenyl group,a naphthyl group, biphenyl group, anthranil group, phenanthryl group,pyrenyl group, chrysenyl group, fluoranthenyl group, fluorenyl group andthe like are preferable.

L represents a link group. Specifically, L represents a substituted orunsubstituted arylene group having 6 to 50 carbon atoms forming a ring,a substituted or unsubstituted heteroarylene group having 5 to 50 atomsforming a ring, a divalent group formed by singly bonding, ether-bondingor thioether-bonding two or more arylene groups, a divalent group formedby bonding two or more arylene groups by alkylene group having 1 to 20carbon atoms, alkenylene group having 2 to 20 carbon atoms or aminogroup, a divalent group formed by singly bonding, ether-bonding orthioether-bonding two or more heteroarylene groups, or a divalent groupformed by bonding two or more heteroarylene groups by alkylene grouphaving 1 to 20 carbon atoms, alkenylene group having 2 to 20 carbonatoms or amino group. Examples of the arylene group having 6 to 50 ringcarbon atoms are a 1,4-phenylene group, 1,2-phenylene group,1,3-phenylene group, 1,4-naphthylene group, 2,6-naphthylene group,1,5-naphthylene group, 9,10-anthranylene group, 9,10-phenanthrenylenegroup, 3,6-phenanthrenylene group, 1,6-pyrenylene group, 2,7-pyrenylenegroup, 6,12-chrysenylene group, 4-4′-biphenylene group, 3,3′-biphenylenegroup, 2,2′-biphenylene group, 2,7-fluorenylene group and the like.Examples of the arylene group having 5 to 50 ring atoms are a2,5-thiophenylene group, 2,5-silolylene group, 2,5-oxadiazolylene andthe like. Among the above, a 1,4-phenylene group, 1,2-phenylene group,1,3-phenylene group, 1,4-naphthylene group, 9,10-anthranylene group,6,12-chrysenylene group, 4-4′-biphenylene group, 3,3′-biphenylene group,2,2′-biphenylene group, and 2,7-fluorenylene group are preferable.

When L represents a link group formed of 2 or more arylene groups or 2or more heteroarylene groups, adjacent arylene groups or adjacentheteroarylene groups may be bonded together via a divalent group to forma new ring. Examples of the divalent group for forming the ring are atetramethylene group, a pentamethylene group, a hexamethylene group, adiphenylmethane-2,2′-diyl group, a diphenylethane-3,3′-diyl group, adiphenylpropane-4,4′-diyl group and the like.

Examples of a substituent for each of Ar¹ to Ar⁴ and L are an aminogroup, a halogen group, a cyano group, a nitro group and a hydroxy groupeach of which is substituted by a substituted or unsubstituted arylgroup having 6 to 50 carbon atoms forming a ring, a substituted orunsubstituted heteroaryl group having 5 to 50 atoms forming a ring, asubstituted or unsubstituted alkyl group having 1 to 50 carbon atoms, asubstituted or unsubstituted cycloalkyl group having 3 to 50 carbonatoms, a substituted or unsubstituted alkoxy group having 1 to 50 carbonatoms, a substituted or unsubstituted aralkyl group having 7 to 50carbon atoms, a substituted or unsubstituted aryloxy group having 6 to50 carbon atoms forming a ring, a substituted or unsubstitutedheteroaryloxy group having 5 to 50 carbon atoms forming a ring, asubstituted or unsubstituted arylthio group having 6 to 50 atoms forminga ring, a substituted or unsubstituted heteroarylthio group having 5 to50 atoms forming a ring, a substituted or unsubstituted alkoxycarbonylgroup having 2 to 50 carbon atoms, a substituted or unsubstituted arylgroup having 6 to 50 carbon atoms forming a ring, or a substituted orunsubstituted heteroaryl group having 5 to 50 atoms forming a ring.

Examples of the substituted or unsubstituted aryl group having 6 to 50ring carbon atoms are a phenyl group, 1-naphthyl group, 2-naphthylgroup, 1-anthryl group, 2-anthryl group, 9-anthryl group, 1-phenanthrylgroup, 2-phenanthryl group, 3-phenanthryl group, 4-phenanthryl group,9-phenanthryl group, 1-naphthacenyl group, 2-naphthacenyl group,9-naphthacenyl group, 1-pyrenyl group, 2-pyrenyl group, 4-pyrenyl group,2-biphenylyl group, 3-biphenylyl group, 4-biphenylyl group,p-terphenyl-4-yl group, p-terphenyl-3-yl group, p-terphenyl-2-yl group,m-terphenyl-4-yl group, m-terphenyl-3-yl group, m-terphenyl-2-yl group,o-tolyl group, m-tolyl group, p-tolyl group, p-t-butylphenyl group,p-(2-phenylpropyl)phenyl group, 3-methyl-2-naphthyl group,4-methyl-1-naphthyl group, 4-methyl-1-anthryl group, 4′-methylbiphenylylgroup, 4″-t-butyl-p-terphenyl-4-yl group, fluoranthenyl group, fluorenylgroup and the like.

Examples of the substituted or unsubstituted heteroaryl group having 5to 50 ring atoms are a 1-pyroryl group, 2-pyroryl group, 3-pyrorylgroup, pyrazinyl group, 2-pyridiny group, 3-pyridinyl group, 4-pyridinylgroup, 1-indolyl group, 2-indolyl group, 3-indolyl group, 4-indolylgroup, 5-indolyl group, 6-indolyl group, 7-indolyl group, 1-isoindolylgroup, 2-isoindolyl group, 3-isoindolyl group, 4-isoindolyl group,5-isoindolyl group, 6-isoindolyl group, 7-isoindolyl group, 2-furylgroup, 3-furyl group, 2-benzofuranyl group, 3-benzofuranyl group,4-benzofuranyl group, 5-benzofuranyl group, 6-benzofuranyl group,7-benzofuranyl group, 1-isobenzofuranyl group, 3-isobenzofuranyl group,4-isobenzofuranyl group, 5-isobenzofuranyl group, 6-isobenzofuranylgroup, 7-isobenzofuranyl group, quinolyl group, 3-quinolyl group,4-quinolyl group, 5-quinolyl group, 6-quinolyl group, 7-quinolyl group,8-quinolyl group, 1-isoquinolyl group, 3-isoquinolyl group,4-isoquinolyl group, 5-isoquinolyl group, 6-isoquinolyl group,7-isoquinolyl group, 8-isoquinolyl group, 2-quinoxalinyl group,5-quinoxalinyl group, 6-quinoxalinyl group, 1-carbazolyl group,2-carbazolyl group, 3-carbazolyl group, 4-carbazolyl group, 9-carbazolylgroup, 1-phenanthrydinyl group, 2-phenanthrydinyl group,3-phenanthrydinyl group, 4-phenanthrydinyl group, 6-phenanthrydinylgroup, 7-phenanthrydinyl group, 8-phenanthrydinyl group,9-phenanthrydinyl group, 10-phenanthrydinyl group, 1-acridinyl group,2-acridinyl group, 3-acridinyl group, 4-acridinyl group, 9-acridinylgroup, 1,7-phenanthroline-2-yl group, 1,7-phenanthroline-3-yl group,1,7-phenanthroline-4-yl group, 1,7-phenanthroline-5-yl group,1,7-phenanthroline-6-yl group, 1,7-phenanthroline-8-yl group,1,7-phenanthroline-9-yl group, 1,7-phenanthroline-10-yl group,1,8-phenanthroline-2-yl group, 1,8-phenanthroline-3-yl group,1,8-phenanthroline-4-yl group, 1,8-phenanthroline-5-yl group,1,8-phenanthroline-6-yl group, 1,8-phenanthroline-7-yl group,1,8-phenanthroline-9-yl group, 1,8-phenanthroline-10-yl group,1,9-phenanthroline-2-yl group, 1,9-phenanthroline-3-yl group,1,9-phenanthroline-4-yl group, 1,9-phenanthroline-5-yl group,1,9-phenanthroline-6-yl group, 1,9-phenanthroline-7-yl group,1,9-phenanthroline-8-yl group, 1,9-phenanthroline-10-yl group,1,10-phenanthroline-2-yl group, 1,10-phenanthroline-3-yl group,1,10-phenanthroline-4-yl group, 1,10-phenanthroline-5-yl group,2,9-phenanthroline-1-yl group, 2,9-phenanthroline-3-yl group,2,9-phenanthroline-4-yl group, 2,9-phenanthroline-5-yl group,2,9-phenanthroline-6-yl group, 2,9-phenanthroline-7-yl group,2,9-phenanthroline-8-yl group, 2,9-phenanthroline-10-yl group,2,8-phenanthroline-1-yl group, 2,8-phenanthroline-3-yl group,2,8-phenanthroline-4-yl group, 2,8-phenanthroline-5-yl group,2,8-phenanthroline-6-yl group, 2,8-phenanthroline-7-yl group,2,8-phenanthroline-9-yl group, 2,8-phenanthroline-10-yl group,2,7-phenanthroline-1-yl group, 2,7-phenanthroline-3-yl group,2,7-phenanthroline-4-yl group, 2,7-phenanthroline-5-yl group,2,7-phenanthroline-6-yl group, 2,7-phenanthroline-8-yl group,2,7-phenanthroline-9-yl group, 2,7-phenanthroline-10-yl group,1-phenazinyl group, 2-phenazinyl group, 1-phenothiazinyl group,2-phenothiazinyl group, 3-phenothiazinyl group, 4-phenothiazinyl group,10-phenothiazinyl group, 1-phenoxazinyl group, 2-phenoxazinyl group,3-phenoxazinyl group, 4-phenoxazinyl group, 10-phenoxazinyl group,2-oxazolyl group, 4-oxazolyl group, 5-oxazolyl group, 2-oxadiazolylgroup, 5-oxadiazolyl group, 3-furazanyl group, 2-thienyl group,3-thienyl group, 2-methylpyrrole-1-yl group, 2-methylpyrrole-3-yl group,2-methylpyrrole-4-yl group, 2-methylpyrrole-5-yl group,3-methylpyrrole-1-yl group, 3-methylpyrrole-2-yl group,3-methylpyrrole-4-yl group, 3-methylpyrrole-5-yl group,2-t-butylpyrrole-3-yl group, 3-(2-phenylpropyl)pyrrole-1-yl group,2-methyl-1-indolyl group, 4-methyl-1-indolyl group, 2-methyl-3-indolylgroup, 4-methyl-3-indolyl group, 2-t-butyl-1-indolyl group,4-t-butyl-1-indolyl group, 2-t-butyl-3-indolyl group,4-t-butyl-3-indolyl group and the like.

Examples of the substituted or unsubstituted alkyl group having 1 to 50carbon atoms are a methyl group, ethyl group, propyl group, isopropylgroup, n-butyl group, s-butyl group, isobutyl group, t-butyl group,n-pentyl group, n-hexyl group, n-heptyl group, n-octyl group,hydroxymethyl group, 1-hydroxyethyl group, 2-hydroxyethyl group,2-hydroxyisobutyl group, 1,2-dihydroroxyethyl group,1,3-dihydroxyisopropyl group, 2,3-dihydroxy-t-butyl group,1,2,3-trihydroxypropyl group, chloromethyl group, 1-chloroethyl group,2-chloroethyl group, 2-chloroisobutyl group, 1,2-dichloroethyl group,1,3-dichloroisopropyl group, 2,3-dichloro-t-butyl group,1,2,3-trichloropropyl group, bromomethyl group, 1-bromoethyl group,2-bromoethyl group, 2-bromoisobutyl group, 1,2-dibromoethyl group,1,3-dibromoisopropyl group, 2,3-dibromo-t-butyl group,1,2,3-tribromopropyl group, iodomethyl group, 1-iodoethyl group,2-iodoethyl group, 2-iodoisobutyl group, 1,2-diiodoethyl group,1,3-diiodoisopropyl group, 2,3-diiodo-t-butyl group, 1,2,3-triiodopropylgroup, aminomethyl group, 1-aminoethyl group, 2-aminoethyl group,2-aminoisobutyl group, 1,2-diaminoethyl group, 1,3-diaminoisopropylgroup, 2,3-diamino-t-butyl group, 1,2,3-triaminopropyl group,cyanomethyl group, 1-cyanoethyl group, 2-cyanoethyl group,2-cyanoisobutyl group, 1,2-dicyanoethyl group, 1,3-dicyanoisopropylgroup, 2,3-dicyano-t-butyl group, 1,2,3-tricyanopropyl group,nitromethyl group, 1-nitroethyl group, 2-nitroethyl group,2-nitroisobutyl group, 1,2-dinitroethyl group, 1,3-dinitroisopropylgroup, 2,3-dinitro-t-butyl group and 1,2,3-trinitropropyl group.

Examples of the substituted or unsubstituted cycloalkyl group having 3to 50 carbon atoms are a cyclopropyl group, a cyclobutyl group, acyclopentyl group, a cyclohexyl group, a 4-methylcyclohexyl group, a1-adamantyl group, a 2-adamantyl group, a 1-norbornyl group, a2-norbornyl group and the like.

The substituted or unsubstituted alkoxy group having 1 to 50 carbonatoms is a group represented by —OY. Examples of Y are a methyl group,ethyl group, propyl group, isopropyl group, n-butyl group, s-butylgroup, isobutyl group, t-butyl group, n-pentyl group, n-hexyl group,n-heptyl group, n-octyl group, hydroxymethyl group, 1-hydroxyethylgroup, 2-hydroxyethyl group, 2-hydroxyisobutyl group,1,2-dihydroroxyethyl group, 1,3-dihydroxyisopropyl group,2,3-dihydroxy-t-butyl group, 1,2,3-trihydroxypropyl group, chloromethylgroup, 1-chloroethyl group, 2-chloroethyl group, 2-chloroisobutyl group,1,2-dichloroethyl group, 1,3-dichloroisopropyl group,2,3-dichloro-t-butyl group, 1,2,3-trichloropropyl group, bromomethylgroup, 1-bromoethyl group, 2-bromoethyl group, 2-bromoisobutyl group,1,2-dibromoethyl group, 1,3-dibromoisopropyl group, 2,3-dibromo-t-butylgroup, 1,2,3-tribromopropyl group, iodomethyl group, 1-iodoethyl group,2-iodoethyl group, 2-iodoisobutyl group, 1,2-diiodoethyl group,1,3-diiodoisopropyl group, 2,3-diiodo-t-butyl group, 1,2,3-triiodopropylgroup, aminomethyl group, 1-aminoethyl group, 2-aminoethyl group,2-aminoisobutyl group, 1,2-diaminoethyl group, 1,3-diaminoisopropylgroup, 2,3-diamino-t-butyl group, 1,2,3-triaminopropyl group,cyanomethyl group, 1-cyanoethyl group, 2-cyanoethyl group,2-cyanoisobutyl group, 1,2-dicyanoethyl group, 1,3-dicyanoisopropylgroup, 2,3-dicyano-t-butyl group, 1,2,3-tricyanopropyl group,nitromethyl group, 1-nitroethyl group, 2-nitroethyl group,2-nitroisobutyl group, 1,2-dinitroethyl group, 1,3-dinitroisopropylgroup, 2,3-dinitro-t-butyl group and 1,2,3-trinitropropyl group.

Examples of the substituted or unsubstituted aralkyl group having 7 to50 carbon atoms are a benzyl group, 1-phenylethyl group, 2-phenylethylgroup, 1-phenylisopropyl group, 2-phenylisopropyl group, phenyl-t-butylgroup, α-naphthylmethyl group, 1-α-naphthylethyl group,2-α-naphthylethyl group, 1-α-naphthylisopropyl group,2-α-naphthylisopropyl group, β-naphthylmethyl group, 1-β-naphthylethylgroup, 2-β-naphthylethyl group, 1-β-naphthylisopropyl group,2-β-naphthylisopropyl group, 1-pyrorylmethyl group, 2-(1-pyroryl)ethylgroup, p-methylbenzyl group, m-methylbenzyl group, o-methylbenzyl group,p-chlorobenzyl group, m-chlorobenzyl group, o-chlorobenzyl group,p-bromobenzyl group, m-bromobenzyl group, o-bromobenzyl group,p-iodobenzyl group, m-iodobenzyl group, o-iodobenzyl group,p-hydroxybenzyl group, m-hydroxybenzyl group, o-hydroxybenzyl group,p-aminobenzyl group, m-aminobenzyl group, o-aminobenzyl group,p-nitrobenzyl group, m-nitrobenzyl group, o-nitrobenzyl group,p-cyanobenzyl group, m-cyanobenzyl group, o-cyanobenzyl group,1-hydroxy-2-phenylisopropyl group, 1-chloro-2-phenylisopropyl group andthe like.

The substituted or unsubstituted aryloxy group having 6 to 50 ringcarbon atoms is represented by —OY′. Preferable examples of Y′ are aphenyl group, 1-naphthyl group, 2-naphthyl group, 1-anthryl group,2-anthryl group, 9-anthryl group, 1-phenanthryl group, 2-phenanthrylgroup, 3-phenanthryl group, 4-phenanthryl group, 9-phenanthryl group,1-naphthacenyl group, 2-naphthacenyl group, 9-naphthacenyl group,1-pyrenyl group, 2-pyrenyl group, 4-pyrenyl group, 2-biphenylyl group,3-biphenylyl group, 4-biphenylyl group, p-terphenyl-4-yl group,p-terphenyl-3-yl group, p-terphenyl-2-yl group, m-terphenyl-4-yl group,m-terphenyl-3-yl group, m-terphenyl-2-yl group, o-tolyl group, m-tolylgroup, p-tolyl group, p-t-butylphenyl group, p-(2-phenylpropyl)phenylgroup, 3-methyl-2-naphthyl group, 4-methyl-1-naphthyl group,4-methyl-1-anthryl group, 4′-methylbiphenylyl group,4″-t-butyl-p-terphenyl-4-yl group and the like.

The substituted or unsubstituted heteroaryloxy group having 5 to 50 ringatoms is represented by —OZ′. Examples of Z′ are a 2-pyroryl group,3-pyroryl group, pyrazinyl group, 2-pyridiny group, 3-pyridinyl group,4-pyridinyl group, 2-indolyl group, 3-indolyl group, 4-indolyl group,5-indolyl group, 6-indolyl group, 7-indolyl group, 1-isoindolyl group,3-isoindolyl group, 4-isoindolyl group, 5-isoindolyl group, 6-isoindolylgroup, 7-isoindolyl group, 2-furyl group, 3-furyl group, 2-benzofuranylgroup, 3-benzofuranyl group, 4-benzofuranyl group, 5-benzofuranyl group,6-benzofuranyl group, 7-benzofuranyl group, 1-isobenzofuranyl group,3-isobenzofuranyl group, 4-isobenzofuranyl group, 5-isobenzofuranylgroup, 6-isobenzofuranyl group, 7-isobenzofuranyl group, 2-quinolylgroup, 3-quinolyl group, 4-quinolyl group, 5-quinolyl group, 6-quinolylgroup, 7-quinolyl group, 8-quinolyl group, 1-isoquinolyl group,3-isoquinolyl group, 4-isoquinolyl group, 5-isoquinolyl group,6-isoquinolyl group, 7-isoquinolyl group, 8-isoquinolyl group,2-quinoxalinyl group, 5-quinoxalinyl group, 6-quinoxalinyl group,1-carbazolyl group, 2-carbazolyl group, 3-carbazolyl group, 4-carbazolylgroup, 1-phenanthrydinyl group, 2-phenanthrydinyl group,3-phenanthrydinyl group, 4-phenanthrydinyl group, 6-phenanthrydinylgroup, 7-phenanthrydinyl group, 8-phenanthrydinyl group,9-phenanthrydinyl group, 10-phenanthrydinyl group, 1-acridinyl group,2-acridinyl group, 3-acridinyl group, 4-acridinyl group, 9-acridinylgroup, 1,7-phenanthroline-2-yl group, 1,7-phenanthroline-3-yl group,1,7-phenanthroline-4-yl group, 1,7-phenanthroline-5-yl group,1,7-phenanthroline-6-yl group, 1,7-phenanthroline-8-yl group,1,7-phenanthroline-9-yl group, 1,7-phenanthroline-10-yl group,1,8-phenanthroline-2-yl group, 1,8-phenanthroline-3-yl group,1,8-phenanthroline-4-yl group, 1,8-phenanthroline-5-yl group,1,8-phenanthroline-6-yl group, 1,8-phenanthroline-7-yl group,1,8-phenanthroline-9-yl group, 1,8-phenanthroline-10-yl group,1,9-phenanthroline-2-yl group, 1,9-phenanthroline-3-yl group,1,9-phenanthroline-4-yl group, 1,9-phenanthroline-5-yl group,1,9-phenanthroline-6-yl group, 1,9-phenanthroline-7-yl group,1,9-phenanthroline-8-yl group, 1,9-phenanthroline-10-yl group,1,10-phenanthroline-2-yl group, 1,10-phenanthroline-3-yl group,1,10-phenanthroline-4-yl group, 1,10-phenanthroline-5-yl group,2,9-phenanthroline-1-yl group, 2,9-phenanthroline-3-yl group,2,9-phenanthroline-4-yl group, 2,9-phenanthroline-5-yl group,2,9-phenanthroline-6-yl group, 2,9-phenanthroline-7-yl group,2,9-phenanthroline-8-yl group, 2,9-phenanthroline-10-yl group,2,8-phenanthroline-1-yl group, 2,8-phenanthroline-3-yl group,2,8-phenanthroline-4-yl group, 2,8-phenanthroline-5-yl group,2,8-phenanthroline-6-yl group, 2,8-phenanthroline-7-yl group,2,8-phenanthroline-9-yl group, 2,8-phenanthroline-10-yl group,2,7-phenanthroline-1-yl group, 2,7-phenanthroline-3-yl group,2,7-phenanthroline-4-yl group, 2,7-phenanthroline-5-yl group,2,7-phenanthroline-6-yl group, 2,7-phenanthroline-8-yl group,2,7-phenanthroline-9-yl group, 2,7-phenanthroline-10-yl group,1-phenazinyl group, 2-phenazinyl group, 1-phenothiazinyl group,2-phenothiazinyl group, 3-phenothiazinyl group, 4-phenothiazinyl group,1-phenoxazinyl group, 2-phenoxazinyl group, 3-phenoxazinyl group,4-phenoxazinyl group, 2-oxazolyl group, 4-oxazolyl group, 5-oxazolylgroup, 2-oxadiazolyl group, 5-oxadiazolyl group, 3-furazanyl group,2-thienyl group, 3-thienyl group, 2-methylpyrrole-1-yl group,2-methylpyrrole-3-yl group, 2-methylpyrrole-4-yl group,2-methylpyrrole-5-yl group, 3-methylpyrrole-1-yl group,3-methylpyrrole-2-yl group, 3-methylpyrrole-4-yl group,3-methylpyrrole-5-yl group, 2-t-butylpyrrole-3-yl group,3-(2-phenylpropyl)pyrrole-1-yl group, 2-methyl-1-indolyl group,4-methyl-1-indolyl group, 2-methyl-3-indolyl group, 4-methyl-3-indolylgroup, 2-t-butyl-1-indolyl group, 4-t-butyl-1-indolyl group,2-t-butyl-3-indolyl group, 4-t-butyl-3-indolyl group and the like.

The substituted or unsubstituted arylthio group having 6 to 50 ringcarbon atoms is represented by —SY″. Preferable examples of Y″ are aphenyl group, 1-naphthyl group, 2-naphthyl group, 1-anthryl group,2-anthryl group, 9-anthryl group, 1-phenanthryl group, 2-phenanthrylgroup, 3-phenanthryl group, 4-phenanthryl group, 9-phenanthryl group,1-naphthacenyl group, 2-naphthacenyl group, 9-naphthacenyl group,1-pyrenyl group, 2-pyrenyl group, 4-pyrenyl group, 2-biphenylyl group,3-biphenylyl group, 4-biphenylyl group, p-terphenyl-4-yl group,p-terphenyl-3-yl group, p-terphenyl-2-yl group, m-terphenyl-4-yl group,m-terphenyl-3-yl group, m-terphenyl-2-yl group, o-tolyl group, m-tolylgroup, p-tolyl group, p-t-butylphenyl group, p-(2-phenylpropyl)phenylgroup, 3-methyl-2-naphthyl group, 4-methyl-1-naphthyl group,4-methyl-1-anthryl group, 4′-methylbiphenylyl group,4″-t-butyl-p-terphenyl-4-yl group and the like.

The substituted or unsubstituted heteroarylthio group is represented by—SZ″. Examples of Z″ are a 2-pyroryl group, 3-pyroryl group, pyrazinylgroup, 2-pyridiny group, 3-pyridinyl group, 4-pyridinyl group, 2-indolylgroup, 3-indolyl group, 4-indolyl group, 5-indolyl group, 6-indolylgroup, 7-indolyl group, 1-isoindolyl group, 3-isoindolyl group,4-isoindolyl group, 5-isoindolyl group, 6-isoindolyl group, 7-isoindolylgroup, 2-furyl group, 3-furyl group, 2-benzofuranyl group,3-benzofuranyl group, 4-benzofuranyl group, 5-benzofuranyl group,6-benzofuranyl group, 7-benzofuranyl group, 1-isobenzofuranyl group,3-isobenzofuranyl group, 4-isobenzofuranyl group, 5-isobenzofuranylgroup, 6-isobenzofuranyl group, 7-isobenzofuranyl group, 2-quinolylgroup, 3-quinolyl group, 4-quinolyl group, 5-quinolyl group, 6-quinolylgroup, 7-quinolyl group, 8-quinolyl group, 1-isoquinolyl group,3-isoquinolyl group, 4-isoquinolyl group, 5-isoquinolyl group,6-isoquinolyl group, 7-isoquinolyl group, 8-isoquinolyl group,2-quinoxalinyl group, 5-quinoxalinyl group, 6-quinoxalinyl group,1-carbazolyl group, 2-carbazolyl group, 3-carbazolyl group, 4-carbazolylgroup, 1-phenanthrydinyl group, 2-phenanthrydinyl group,3-phenanthrydinyl group, 4-phenanthrydinyl group, 6-phenanthrydinylgroup, 7-phenanthrydinyl group, 8-phenanthrydinyl group,9-phenanthrydinyl group, 10-phenanthrydinyl group, 1-acridinyl group,2-acridinyl group, 3-acridinyl group, 4-acridinyl group, 9-acridinylgroup, 1,7-phenanthroline-2-yl group, 1,7-phenanthroline-3-yl group,1,7-phenanthroline-4-yl group, 1,7-phenanthroline-5-yl group,1,7-phenanthroline-6-yl group, 1,7-phenanthroline-8-yl group,1,7-phenanthroline-9-yl group, 1,7-phenanthroline-10-yl group,1,8-phenanthroline-2-yl group, 1,8-phenanthroline-3-yl group,1,8-phenanthroline-4-yl group, 1,8-phenanthroline-5-yl group,1,8-phenanthroline-6-yl group, 1,8-phenanthroline-7-yl group,1,8-phenanthroline-9-yl group, 1,8-phenanthroline-10-yl group,1,9-phenanthroline-2-yl group, 1,9-phenanthroline-3-yl group,1,9-phenanthroline-4-yl group, 1,9-phenanthroline-5-yl group,1,9-phenanthroline-6-yl group, 1,9-phenanthroline-7-yl group,1,9-phenanthroline-8-yl group, 1,9-phenanthroline-10-yl group,1,10-phenanthroline-2-yl group, 1,10-phenanthroline-3-yl group,1,10-phenanthroline-4-yl group, 1,10-phenanthroline-5-yl group,2,9-phenanthroline-1-yl group, 2,9-phenanthroline-3-yl group,2,9-phenanthroline-4-yl group, 2,9-phenanthroline-5-yl group,2,9-phenanthroline-6-yl group, 2,9-phenanthroline-7-yl group,2,9-phenanthroline-8-yl group, 2,9-phenanthroline-10-yl group,2,8-phenanthroline-1-yl group, 2,8-phenanthroline-3-yl group,2,8-phenanthroline-4-yl group, 2,8-phenanthroline-5-yl group,2,8-phenanthroline-6-yl group, 2,8-phenanthroline-7-yl group,2,8-phenanthroline-9-yl group, 2,8-phenanthroline-10-yl group,2,7-phenanthroline-1-yl group, 2,7-phenanthroline-3-yl group,2,7-phenanthroline-4-yl group, 2,7-phenanthroline-5-yl group,2,7-phenanthroline-6-yl group, 2,7-phenanthroline-8-yl group,2,7-phenanthroline-9-yl group, 2,7-phenanthroline-10-yl group,1-phenazinyl group, 2-phenazinyl group, 1-phenothiazinyl group,2-phenothiazinyl group, 3-phenothiazinyl group, 4-phenothiazinyl group,1-phenoxazinyl group, 2-phenoxazinyl group, 3-phenoxazinyl group,4-phenoxazinyl group, 2-oxazolyl group, 4-oxazolyl group, 5-oxazolylgroup, 2-oxadiazolyl group, 5-oxadiazolyl group, 3-furazanyl group,2-thienyl group, 3-thienyl group, 2-methylpyrrole-1-yl group,2-methylpyrrole-3-yl group, 2-methylpyrrole-4-yl group,2-methylpyrrole-5-yl group, 3-methylpyrrole-1-yl group,3-methylpyrrole-2-yl group, 3-methylpyrrole-4-yl group,3-methylpyrrole-5-yl group, 2-t-butylpyrrole-3-yl group,3-(2-phenylpropyl)pyrrole-1-yl group, 2-methyl-1-indolyl group,4-methyl-1-indolyl group, 2-methyl-3-indolyl group, 4-methyl-3-indolylgroup, 2-t-butyl-1-indolyl group, 4-t-butyl-1-indolyl group,2-t-butyl-3-indolyl group, 4-t-butyl-3-indolyl group and the like.

The alkoxycarbonyl group having 2 to 50 carbon atoms is a grouprepresented by —COOZ. Examples of Z are a methyl group, ethyl group,propyl group, isopropyl group, n-butyl group, s-butyl group, isobutylgroup, t-butyl group, n-pentyl group, n-hexyl group, n-heptyl group,n-octyl group, hydroxymethyl group, 1-hydroxyethyl group, 2-hydroxyethylgroup, 2-hydroxyisobutyl group, 1,2-dihydroroxyethyl group,1,3-dihydroxyisopropyl group, 2,3-dihydroxy-t-butyl group,1,2,3-trihydroxypropyl group, chloromethyl group, 1-chloroethyl group,2-chloroethyl group, 2-chloroisobutyl group, 1,2-dichloroethyl group,1,3-dichloroisopropyl group, 2,3-dichloro-t-butyl group,1,2,3-trichloropropyl group, bromomethyl group, 1-bromoethyl group,2-bromoethyl group, 2-bromoisobutyl group, 1,2-dibromoethyl group,1,3-dibromoisopropyl group, 2,3-dibromo-t-butyl group,1,2,3-tribromopropyl group, iodomethyl group, 1-iodoethyl group,2-iodoethyl group, 2-iodoisobutyl group, 1,2-diiodoethyl group,1,3-diiodoisopropyl group, 2,3-diiodo-t-butyl group, 1,2,3-triiodopropylgroup, aminomethyl group, 1-aminoethyl group, 2-aminoethyl group,2-aminoisobutyl group, 1,2-diaminoethyl group, 1,3-diaminoisopropylgroup, 2,3-diamino-t-butyl group, 1,2,3-triaminopropyl group,cyanomethyl group, 1-cyanoethyl group, 2-cyanoethyl group,2-cyanoisobutyl group, 1,2-dicyanoethyl group, 1,3-dicyanoisopropylgroup, 2,3-dicyano-t-butyl group, 1,2,3-tricyanopropyl group,nitromethyl group, 1-nitroethyl group, 2-nitroethyl group,2-nitroisobutyl group, 1,2-dinitroethyl group, 1,3-dinitroisopropylgroup, 2,3-dinitro-t-butyl group and 1,2,3-trinitropropyl group.

The amino group substituted by the substituted or unsubstituted arylgroup having 6 to 50 ring carbon atoms or the substituted orunsubstituted heteroaryl group having 5 to 50 ring atoms is representedby —NPQ. Examples of P and Q are a phenyl group, 1-naphthyl group,2-naphtyl group, 1-anthryl group, 2-anthryl group, 9-anthryl group,1-phenanthryl group, 2-phenanthryl group, 3-phenanthryl group,4-phenanthryl group, 9-phenanthryl group, 1-naphthacenyl group,2-naphthacenyl group, 9-naphthacenyl group, 1-pyrenyl group, 2-pyrenylgroup, 4-pyrenyl group, 2-biphenylyl group, 3-biphenylyl group,4-biphenylyl group, p-terphenyl-4-yl group, p-terphenyl-3-yl group,p-terphenyl-2-yl group, m-terphenyl-4-yl group, m-terphenyl-3-yl group,m-terphenyl-2-yl group, o-tolyl group, m-tolyl group, p-tolyl group,p-t-butylphenyl group, p-(2-phenylpropyl)phenyl group,3-methyl-2-naphthyl group, 4-methyl-1-naphthyl group, 4-methyl-1-anthrylgroup, 4′-methylbiphenylyl group, 4″-t-butyl-p-terphenyl-4-yl group,2-pyroryl group, 3-pyroryl group, pyrazinyl group, 2-pyridiny group,3-pyridinyl group, 4-pyridinyl group, 2-indolyl group, 3-indolyl group,4-indolyl group, 5-indolyl group, 6-indolyl group, 7-indolyl group,1-isoindolyl group, 3-isoindolyl group, 4-isoindolyl group, 5-isoindolylgroup, 6-isoindolyl group, 7-isoindolyl group, 2-furyl group, 3-furylgroup, 2-benzofuranyl group, 3-benzofuranyl group, 4-benzofuranyl group,5-benzofuranyl group, 6-benzofuranyl group, 7-benzofuranyl group,1-isobenzofuranyl group, 3-isobenzofuranyl group, 4-isobenzofuranylgroup, 5-isobenzofuranyl group, 6-isobenzofuranyl group,7-isobenzofuranyl group, 2-quinolyl group, 3-quinolyl group, 4-quinolylgroup, 5-quinolyl group, 6-quinolyl group, 7-quinolyl group, 8-quinolylgroup, 1-isoquinolyl group, 3-isoquinolyl group, 4-isoquinolyl group,5-isoquinolyl group, 6-isoquinolyl group, 7-isoquinolyl group,8-isoquinolyl group, 2-quinoxalinyl group, 5-quinoxalinyl group,6-quinoxalinyl group, 1-carbazolyl group, 2-carbazolyl group,3-carbazolyl group, 4-carbazolyl group, 1-phenanthrydinyl group,2-phenanthrydinyl group, 3-phenanthrydinyl group, 4-phenanthrydinylgroup, 6-phenanthrydinyl group, 7-phenanthrydinyl group,8-phenanthrydinyl group, 9-phenanthrydinyl group, 10-phenanthrydinylgroup, 1-acridinyl group, 2-acridinyl group, 3-acridinyl group,4-acridinyl group, 9-acridinyl group, 1,7-phenanthroline-2-yl group,1,7-phenanthroline-3-yl group, 1,7-phenanthroline-4-yl group,1,7-phenanthroline-5-yl group, 1,7-phenanthroline-6-yl group,1,7-phenanthroline-8-yl group, 1,7-phenanthroline-9-yl group,1,7-phenanthroline-10-yl group, 1,8-phenanthroline-2-yl group,1,8-phenanthroline-3-yl group, 1,8-phenanthroline-4-yl group,1,8-phenanthroline-5-yl group, 1,8-phenanthroline-6-yl group,1,8-phenanthroline-7-yl group, 1,8-phenanthroline-9-yl group,1,8-phenanthroline-10-yl group, 1,9-phenanthroline-2-yl group,1,9-phenanthroline-3-yl group, 1,9-phenanthroline-4-yl group,1,9-phenanthroline-5-yl group, 1,9-phenanthroline-6-yl group,1,9-phenanthroline-7-yl group, 1,9-phenanthroline-8-yl group,1,9-phenanthroline-10-yl group, 1,10-phenanthroline-2-yl group,1,10-phenanthroline-3-yl group, 1,10-phenanthroline-4-yl group,1,10-phenanthroline-5-yl group, 2,9-phenanthroline-1-yl group,2,9-phenanthroline-3-yl group, 2,9-phenanthroline-4-yl group,2,9-phenanthroline-5-yl group, 2,9-phenanthroline-6-yl group,2,9-phenanthroline-7-yl group, 2,9-phenanthroline-8-yl group,2,9-phenanthroline-10-yl group, 2,8-phenanthroline-1-yl group,2,8-phenanthroline-3-yl group, 2,8-phenanthroline-4-yl group,2,8-phenanthroline-5-yl group, 2,8-phenanthroline-6-yl group,2,8-phenanthroline-7-yl group, 2,8-phenanthroline-9-yl group,2,8-phenanthroline-10-yl group, 2,7-phenanthroline-1-yl group,2,7-phenanthroline-3-yl group, 2,7-phenanthroline-4-yl group,2,7-phenanthroline-5-yl group, 2,7-phenanthroline-6-yl group,2,7-phenanthroline-8-yl group, 2,7-phenanthroline-9-yl group,2,7-phenanthroline-10-yl group, 1-phenazinyl group, 2-phenazinyl group,1-phenothiazinyl group, 2-phenothiazinyl group, 3-phenothiazinyl group,4-phenothiazinyl group, 1-phenoxazinyl group, 2-phenoxazinyl group,3-phenoxazinyl group, 4-phenoxazinyl group, 2-oxazolyl group, 4-oxazolylgroup, 5-oxazolyl group, 2-oxadiazolyl group, 5-oxadiazolyl group,3-furazanyl group, 2-thienyl group, 3-thienyl group,2-methylpyrrole-1-yl group, 2-methylpyrrole-3-yl group,2-methylpyrrole-4-yl group, 2-methylpyrrole-5-yl group,3-methylpyrrole-1-yl group, 3-methylpyrrole-2-yl group,3-methylpyrrole-4-yl group, 3-methylpyrrole-5-yl group,2-t-butylpyrrole-4-yl group, 3-(2-phenylpropyl)pyrrole-1-yl group,2-methyl-1-indolyl group, 4-methyl-1-indolyl group, 2-methyl-3-indolylgroup, 4-methyl-3-indolyl group, 2-t-butyl-1-indolyl group,4-t-butyl-1-indolyl group, 2-t-butyl-3-indolyl group,4-t-butyl-3-indolyl group and the like.

Examples of the compound represented by the general formula (I) areshown below. However the compound represented by the formula (I) is notlimited thereto.

Aromatic amine represented by the following general formula (II) canalso be preferably used for forming the hole injecting layer or the holetransporting layer.

In the general formula (II), Ar¹ to Ar³ each represent the same as thoserepresented by Ar¹ to Ar⁴ of the general formula (I). Examples of thecompound represented by the general formula (II) are shown below.However, the compound represented by the formula (II) is not limitedthereto.

In the present invention, the anode of the organic EL device is used forinjecting holes into the hole transporting layer or the emitting layer.It is effective that the anode has a work function of 4.5 eV or more.Exemplary materials for the anode used in the present invention areindium-tin oxide (ITO), tin oxide (NESA), gold, silver, platinum andcopper and the like. In order to inject electrons into the electrontransporting layer or the emitting layer, materials having a smallerwork function is preferable for the cathode. Although a material for thecathode is subject to no specific limitation, examples of the materialare indium, aluminum, magnesium, alloy of magnesium and indium, alloy ofmagnesium and aluminum, alloy of aluminum and lithium, alloy ofaluminum, scandium and lithium, alloy of magnesium and silver and thelike.

A method of forming each of the layers in the organic EL deviceaccording to the present invention are not particularly limited. Aconventionally known methods such as vacuum deposition or spin coatingmay be employed for forming the layers. The organic thin-film layercontaining the compound represented by the formula (I), which is used inthe organic EL device according to the present invention, may be formedby a conventional coating method such as vacuum deposition, molecularbeam epitaxy (MBE method) and coating methods using a solution such as adipping, spin coating, casting, bar coating, and roll coating.

Although the thickness of each organic layer of the organic EL device isnot particularly limited, the thickness is generally preferably in arange of several nanometers to 1 μm because excessively-thinned filmlikely entails defects such as a pin hole while excessively-thickenedfilm requires high voltage to be applied and deteriorates efficiency.

The organic EL device is formed on a light-transmissive substrate. Thelight-transmissive plate, which supports the organic EL device, ispreferably a smoothly-shaped substrate that transmits 50% or more oflight in a visible region of 400 to 700 nm.

The light-transmissive plate is exemplarily a glass plate, a polymerplate or the like.

For the glass plate, such materials as soda-lime glass,barium/strontium-containing glass, lead glass, aluminosilicate glass,borosilicate glass, barium borosilicate glass, quartz and the like canbe used.

For the polymer plate, such materials as polycarbonate, acryl,polyethylene terephthalate, polyether sulfide, polysulfone and the likecan be used.

SYNTHESIS EXAMPLE

Next, the present invention will be described in further detail byexemplifying a reference synthesis example and synthesis example(s).However, the present invention is not limited to such synthesisexamples.

Reference Synthesis Example 1-1 Synthesis of 2-(3-bromophenyl)naphthalene

Under an argon gas atmosphere, 243 g (1.41 mol) of 2-naphthaleneboronicacid, 400 g (1.41 mol) of 3-bromoiodobenzene, 3.27 g (28.2 mmol) oftetrakis(triphenylphosphine) palladium(0), 6.4 L of toluene and 3.2 L of2M sodium carbonate solution were mixed, and stirred for 24 hours whilebeing refluxed. After the reaction in the mixture was over, the mixtureexperienced filtration, through which aqueous phase thereof waseliminated. After organic phase thereof was cleansed by water and driedwith magnesium sulfate, toluene was distilled away under reducedpressure. Residue thereof was refined by silica-gel columnchromatography, such that 303 g of 2(3-bromophenyl)naphthalene wasobtained with an yield of 76%.

Reference Synthesis Example 1-2 Synthesis of 3-(2-naphthyl)phenylboronicacid

Under an argon gas atmosphere, a mixture of 212 g (748 mmol) of2-(3-bromophenyl) naphthalene and 3 L of dehydrated THF was cooled downto −10 degrees C., and added with 600 mL (948 mmol) of hexane solutionof 1.6M n-butyllithium in drops while being stirred. Then, the reactionmixture was stirred for one hour at 0 degrees C. The reaction solutionwas further cooled down to −78 degrees C. and added with 450 g (2.39mol) of triisopropyl borate in drops. Subsequently, the reaction mixturewas stirred for 17 hours at room temperature. The reaction mixture wasfurther added with solution of hydrochloric acid to be stirred for onehour at room temperature. The reaction mixture was further added with 3L of toluene, so that aqueous phase thereof was eliminated. Afterorganic phase thereof was dried with magnesium sulfate, the solvent wasdistilled away under reduced pressure. By recrystallizing the obtainedsolid by toluene, 126 g of 3-(2-naphthyl)phenylboronic acid was obtainedat an yield of 67%.

Reference Synthesis Example 2-1 Synthesis of 2-(4-bromophenyl)naphthalene

Under an argon gas atmosphere, 70.0 g (407 mmol) of 2-naphthaleneboronicacid, 115.1 g (407 mmol) of 4-bromoiodobenzene, 9.40 g (8.14 mmol) oftetrakis(triphenylphosphine) palladium(0), 1.2 L of toluene and 600 mLof 2M sodium carbonate solution were mixed, and stirred for 20 hours at90 degrees C. After the reaction in the mixture was over, toluene wasdistilled away therefrom, and the mixture was added with methanol, suchthat precipitated solid was separated by filtration. By recrystallizingthe obtained solid by acetic ether and methanol and subsequently dryingthe solid, 77.2 g of 2-(4-bromophenyl) naphthalene was obtained with anyield of 67%.

Reference Synthesis Example 2-2 Synthesis of 4-(2-naphthyl)phenylboronicacid

Under an argon gas atmosphere, a mixture of 50.0 g (177 mmol) of2-(4-bromophenyl) naphthalene and 500 mL of dehydrated THF was cooleddown to −60 degrees C., and added with 136 mL (212 mmol) of hexanesolution of 1.56M n-butyllithium in drops while being stirred. Then, thereaction mixture was stirred for one hour at −60 degrees C. 99.6 g (529mmol) of triisopropyl borate was dropped into the reaction solution at−60 degrees C. Subsequently, the reaction mixture was warmed up to roomtemperature, and stirred for 18 hours. The reaction mixture was furtheradded with solution of hydrochloric acid to be stirred for one hour atroom temperature. After the reaction, the reaction mixture was furtheradded with toluene, so that aqueous phase thereof was eliminated. Afterorganic phase thereof was dried with magnesium sulfate, the solvent wasdistilled away under reduced pressure. By crystallizing the obtainedsolid by toluene, 33.6 g of 4-(2-naphthyl)phenylboronic acid wasobtained at an yield of 84%.

Reference Synthesis Example 3-1 Synthesis of 1-(3-bromophenyl)naphthalene

Under an argon gas atmosphere, 200.0 g (1.163 mol) of1-naphthaleneboronic acid, 329.0 g (1.163 mol) of 3-bromoiodobenzene,26.9 g (23.3 mmol) of tetrakis(triphenylphosphine) palladium(0), 3.7 Lof toluene and 1.74 L of 2M sodium carbonate solution were mixed, andstirred for 24 hours while being refluxed. After the reaction in themixture was over, the mixture experienced filtration, through whichaqueous phase thereof was eliminated. After organic phase thereof wascleansed by water and dried with magnesium sulfate, toluene wasdistilled away under reduced pressure. Residue thereof was refined bysilica-gel column chromatography, such that 250 g of1-(3-bromophenyl)naphthalene was obtained with an yield of 76%.

Reference Synthesis Example 3-2 Synthesis of 3-(1-naphthyl)phenylboronicacid

Under an argon gas atmosphere, a mixture of 200.0 g (706.3 mmol) of1-(3-bromophenyl) naphthalene and 2.1 L of dehydrated THF was cooleddown to −60 degrees C., and added with 543 mL (847 mmol) of hexanesolution of 1.56M n-butyllithium in drops while being stirred. Then, thereaction mixture was stirred for two hours at −60 degrees C. Thereaction solution was further cooled down to −60 degrees C. and addedwith 398.5 g (2.119 mol) of triisopropyl borate in drops. Subsequently,the reaction mixture was warmed up to room temperature, and stirred for17 hours. The reaction mixture was further added with solution ofhydrochloric acid to be stirred for one hour at room temperature. Afterthe reaction, the reaction mixture was further added with toluene, sothat aqueous phase thereof was eliminated. After organic phase thereofwas dried with magnesium sulfate, the solvent was distilled away underreduced pressure. By recrystallizing the obtained solid by toluene, 126g of 3-(1-naphthyl)phenylboronic acid was obtained at an yield of 67%.

Reference Synthesis Example 4-1 Synthesis of 1-(4-bromophenyl)naphthalene

Under an argon gas atmosphere, 200.0 g (1.163 mol) of1-naphthaleneboronic acid, 329.0 g (1.163 mol) of 4-bromoiodobenzene,26.9 g (23.3 mmol) of tetrakis(triphenylphosphine) palladium(0), 3.7 Lof toluene and 1.74 L of 2M sodium carbonate solution were mixed, andstirred for 24 hours at 90 degrees C. After the reaction in the mixturewas over, the mixture experienced filtration, through which aqueousphase thereof was eliminated. After organic phase thereof was cleansedby water and dried with magnesium sulfate, toluene was distilled awayunder reduced pressure. Residue thereof was refined by silica-gel columnchromatography, such that 268 g of 1-(4-bromophenyl)naphthalene wasobtained with an yield of 81%.

Reference Synthesis Example 4-2 Synthesis of 4-(1-naphthyl)phenylboronicacid

Under an argon gas atmosphere, a mixture of 208.8 g (737.4 mmol) of1-(4-bromophenyl) naphthalene and 2.1 L of dehydrated THF was cooleddown to −60 degrees C., and added with 567 mL (884.9 mmol) of hexanesolution of 1.56M n-butyllithium in drops while being stirred. Then, thereaction mixture was stirred for two hours at −60 degree C. 416 g (2.21mol) of triisopropyl borate was dropped into the reaction solution at−60 degrees C. Subsequently, the reaction mixture was stirred for 17hours at room temperature. The reaction mixture was further added withsolution of hydrochloric acid to be stirred for one hour at roomtemperature. After the reaction, the reaction mixture was further addedwith toluene, so that aqueous phase thereof was eliminated. Afterorganic phase thereof was dried with magnesium sulfate, the solvent wasdistilled away under reduced pressure. By recrystallizing the obtainedsolid by toluene, 126 g of 4-(1-naphthyl)phenylboronic acid was obtainedat an yield of 67%.

Reference Synthesis Example 5-1 Synthesis of9-(3-bromophenyl)phenanthrene

Under an argon gas atmosphere, 31.4 g (141 mmol) of9-phenanthreneboronic acid, 40.0 g (141 mmol) of 3-bromoiodobenzene,3.30 g (2.83 mmol) of tetrakis(triphenylphosphine) palladium(0), 200 mLof toluene, 50 mL of dimethoxyethane and 212 mL of 2M sodium carbonatesolution were mixed, and stirred for four hours while being refluxed.After the reaction, the reaction mixture was further added with toluene,and cleansed by water. After organic phase thereof was dried withmagnesium sulfate, the toluene was distilled away under reducedpressure. Residue thereof was refined by silica-gel columnchromatography, such that 34.7 g of 9-(3-bromophenyl)phenanthrene wasobtained with an yield of 74%.

Reference Synthesis Example 5-2 Synthesis of3-(9-phenanthrenyl)phenylboronic acid

Under an argon gas atmosphere, a mixture of 15.45 g (46.4 mmol) of9-(3-bromophenyl)phenanthrene and 150 mL of dehydrated THF was cooleddown to −60 degrees C., and added with 35.9 mL (55.6 mmol) of hexanesolution of 1.55M n-butyllithium in drops while being stirred. Then, thereaction mixture was stirred for two hours at −60 degrees C. Thereaction solution was added with 26.2 g (139 mol) of triisopropyl boratein drops at −60 degrees C. Subsequently, the reaction mixture was warmedup to room temperature, and stirred for one hour. Then, the reactionmixture was left for a night. The solvent was distilled away underreduced pressure, such that the reaction mixture was condensed. Thereaction mixture was cooled down to 0 degree C. to be further added withsolution of hydrochloric acid, and then stirred for one hour at roomtemperature. After the reaction, the reaction mixture was further addedwith dichloromethane, so that aqueous phase thereof was eliminated.After organic phase thereof was dried with magnesium sulfate, thesolvent was distilled away under reduced pressure. Residue thereof wasrefined by silica-gel column chromatography, such that 13.4 g of3-(9-phenanthrenyl)phenylboronic acid was obtained with an yield of 67%.

Reference Synthesis Example 6-1 Synthesis of9-(4-bromophenyl)phenanthrene

Under an argon gas atmosphere, 39.25 g (177 mmol) of9-phenanthreneboronic acid, 50.0 g (177 mmol) of 4-bromoiodobenzene,4.10 g (3.54 mmol) of tetrakis(triphenylphosphine) palladium(0), 400 mLof toluene and 265 mL of 2M sodium carbonate solution were mixed, andstirred for 24 hours while being refluxed. After the reaction in themixture was over, the mixture experienced filtration, through whichaqueous phase thereof was eliminated. After organic phase thereof wascleansed by water and dried with magnesium sulfate, toluene wasdistilled away under reduced pressure. Residue thereof was refined bysilica-gel column chromatography, such that 42.6 g of9-(4-bromophenyl)phenanthrene was obtained with an yield of 72%.

Reference Synthesis Example 6-2 Synthesis of4-(9-phenanthrenyl)phenylboronic acid

Under an argon gas atmosphere, a mixture of 21.3 g (63.9 mmol) of9-(4-bromophenyl)phenanthrene and 200 mL of dehydrated THF was cooleddown to −60 degrees C., and added with 49.2 mL (76.7 mmol) of hexanesolution of 1.56M n-butyllithium in drops while being stirred. Then, thereaction mixture was stirred for two hours at −60 degrees C. Thereaction solution was further cooled down to −60 degrees C. and addedwith 36.1 g (192 mol) of triisopropyl borate in drops. Subsequently, thereaction mixture was warmed up to room temperature, and stirred for 17hours. The reaction mixture was cooled down to 0 degree C. to be furtheradded with solution of hydrochloric acid, and then stirred for one hourat room temperature. After the reaction, the reaction mixture wasfurther added with toluene, so that aqueous phase thereof waseliminated. After organic phase thereof was dried with magnesiumsulfate, the solvent was distilled away under reduced pressure. Byrecrystallizing residue by toluene and hexane, 13.8 g of4-(9-phenanthrenyl)phenylboronic acid was obtained at an yield of 72%.

Synthesis Example 1-1 Synthesis of Compound 1-5

Under an argon gas atmosphere, 10.0 g (35.0 mmol) of2,6-dibromonaphthalene, 8.68 g (35.0 mmol) of3-(1-naphthyl)phenylboronic acid, 0.81 g (0.70 mmol) oftetrakis(triphenylphosphine) palladium(0), 200 mL of toluene, 50 mL ofdimethoxyethane and 48 mL of 2M sodium carbonate solution were mixed,and stirred for 10 hours at 90 degrees C. Subsequently, the reactionmixture was cooled down to room temperature, added with water andstirred for one hour. Then, the reaction mixture was extracted bytoluene. After liquid separation, organic phase thereof was cleansedwith saturated saline solution and dried with anhydrous sodium sulfate.The solvent was distilled away under reduced pressure, and the residuewas refined by silica-gel column chromatography and recrystallized bytoluene, such that 4.20 g of 2-bromo-6-(3-(naphthalene-1-yl)phenyl)naphthalene was obtained at an yield of 29%.

Under an argon gas atmosphere, 4.20 g (10.3 mmol) of2-bromo-6-(3-(naphthalene-1-yl)phenyl)naphthalene, 1.85 g (10.8 mmol) of4-(2-naphthyl)phenylboronic acid, 0.24 g (0.21 mmol) oftetrakis(triphenylphosphine) palladium(0), 100 mL of toluene, and 15.4mL of 2M sodium carbonate solution were mixed, and stirred for 10 hoursat 90 degrees C. Subsequently, the reaction mixture was cooled down toroom temperature, added with water and stirred for one hour at roomtemperature. After solid was separated by filtration, the obtained solidwas cleansed with water, methanol, dimethoxyethane and toluene in thisorder. By dissolving the obtained solid in toluene, refining thesolution by silica-gel column chromatography and further recrystallizingthe solution by toluene, 2.80 g of the compound 1-5 was obtained at anyield of 51%.

Mass-spectrum analysis consequently showed that m/e was equal to 532while a calculated molecular weight was 532.22.

Synthesis Example 1-2 Synthesis of Compound 1-9

The compound 1-9 was synthesized by the same method as the compound 1-5except that 3-(2-naphthyl)phenylboronic acid was used in place of3-(1-naphthyl)phenylboronic acid.

Mass-spectrum analysis consequently showed that m/e was equal to 532while a calculated molecular weight was 532.22.

Synthesis Example 1-3 Synthesis of Compound 1-11

The compound 1-11 was synthesized by the same method as the compound 1-5except that 3-(2-naphthyl)phenylboronic acid was used in place of3-(1-naphthyl)phenylboronic acid and that 1,5-dibromonaphthalene wasused in place of 2,6-dibromonaphthalene.

Mass-spectrum analysis consequently showed that m/e was equal to 532while a calculated molecular weight was 532.22.

Synthesis Example 1-4 Synthesis of Compound 1-17

The compound 1-17 was synthesized by the same method as the compound 1-5except that 4-(2-naphthyl)phenylboronic acid was used in place of3-(1-naphthyl)phenylboronic acid and that 4-biphenylboronic acid wasused in place of 4-(2-naphthyl)phenylboronic acid.

Mass-spectrum analysis consequently showed that m/e was equal to 482while a calculated molecular weight was 482.2.

Synthesis Example 1-5 Synthesis of Compound 1-18

The compound 1-18 was synthesized by the same method as the compound 1-5except that 4-(2-naphthyl)phenylboronic acid was used in place of3-(1-naphthyl)phenylboronic acid, that 1,4-dibromonaphthalene was usedin place of 2,6-dibromonaphthalene, and that 4-biphenylboronic acid wasused in place of 4-(2-naphthyl)phenylboronic acid.

Mass-spectrum analysis consequently showed that m/e was equal to 482while a calculated molecular weight was 482.2.

Synthesis Example 1-6 Synthesis of Compound 1-21

The compound 1-21 was synthesized by the same method as the compound 1-5except that 4-(1-naphthyl)phenylboronic acid was used in place of3-(1-naphthyl)phenylboronic acid and that4-(9-phenanthrenyl)phenylboronic acid was used in place of4-(2-naphthyl)phenylboronic acid.

Mass-spectrum analysis consequently showed that m/e was equal to 582while a calculated molecular weight was 582.23.

Synthesis Example 1-7 Synthesis of Compound 1-30

The compound 1-30 was synthesized by the same method as the compound 1-5except that 3-(2-naphthyl)phenylboronic acid was used in place of3-(1-naphthyl)phenylboronic acid, that 1,4-dibromonaphthalene was usedin place of 2,6-dibromonaphthalene, and that4-(9-phenanthrenyl)phenylboronic acid was used in place of4-(2-naphthyl)phenylboronic acid.

Mass-spectrum analysis consequently showed that m/e was equal to 582while a calculated molecular weight was 582.23.

Synthesis Example 1-8 Synthesis of Compound 1-33

The compound 1-33 was synthesized by the same method as the compound 1-5except that 4-(2-naphthyl)phenylboronic acid was used in place of3-(1-naphthyl)phenylboronic acid and that4-(9-phenanthrenyl)phenylboronic acid was used in place of4-(2-naphthyl)phenylboronic acid.

Mass-spectrum analysis consequently showed that m/e was equal to 582while a calculated molecular weight was 582.23.

Synthesis Example 1-9 Synthesis of Compound 1-37

The compound 1-37 was synthesized by the same method as the compound 1-5except that 4-(2-naphthyl)phenylboronic acid was used in place of3-(1-naphthyl)phenylboronic acid, that 1,5-dibromonaphthalene was usedin place of 2,6-dibromonaphthalene, and that3-(9-phenanthrenyl)phenylboronic acid was used in place of4-(2-naphthyl)phenylboronic acid.

Mass-spectrum analysis consequently showed that m/e was equal to 582while a calculated molecular weight was 582.23.

Synthesis Example 1-10 Synthesis of Compound 1-39

The compound 1-39 was synthesized by the same method as the compound 1-5except that 4-(2-naphthyl)phenylboronic acid was used in place of3-(1-naphthyl)phenylboronic acid and that3-(9-phenanthrenyl)phenylboronic acid was used in place of4-(2-naphthyl)phenylboronic acid.

Mass-spectrum analysis consequently showed that m/e was equal to 582while a calculated molecular weight was 582.23.

A machine used in the measurement of mass spectrometry and measurementconditions thereof in the above synthesis examples will be describedbelow.

Machine: JSM-700 (manufactured by Japan Electron Optics LaboratoriesLtd.)

Conditions: accelerating voltage of 8 kV

Scan range m/z of 50 to 3000

Emitter type: carbon

emitter current: 0 mA→2 mA/minute→40 mA (maintained for 10 minutes)

EXAMPLES

Next, the present invention will be described in further detail byexemplifying Example(s). However, the present invention is not limitedto Example(s).

Structures of compounds used in Examples and Comparatives will be shownbelow.

Example 1 Manufacturing of Organic EL Device

A glass substrate (size: 25 mm×75 mm×0.7 mm thick) having an ITOtransparent electrode (manufactured by Asahi Glass Co., Ltd) wasultrasonic-cleaned in isopropyl alcohol for five minutes, and thenUV/ozone-cleaned for 30 minutes. After the glass substrate having thetransparent electrode line was cleaned, the glass substrate was mountedon a vacuum deposition apparatus, so that 50-nm thick film of HT1 wasinitially formed to cover a surface of the glass substrate where thetransparent electrode line was provided. The HT1 film serves as a holeinjecting/transporting layer. Subsequently to the formation of the holeinjecting/transporting layer, 40-nm thick film of a new host compound1-5 and a film of Ir(piq)₃ as a phosphorescent dopant were co-evaporatedby resistance heating so that Ir(piq)₃ was contained therein with acontent of 10 mass %. The co-deposited film serves as an emitting layer(phosphorescent emitting layer). After the film of the emitting layerwas formed, 40-nm thick film of ET1 was formed. The film of ET1 servesas an electron transporting layer. Then, 0.5-nm thick film of LiF wasformed as an electron-injecting electrode (cathode) at a film-formingspeed of 1 Å/min. Metal (Al) was vapor-deposited on the LiF film to forma 150-nm thick metal cathode, thereby providing the organic EL device.

Examples 2 to 10 and Comparatives 1 to 3

The organic EL devices according respectively to Examples 2 to 10 andComparatives 1 to 3 are formed by the same method as Example 1 exceptthat host compounds shown in Table 1 were respectively used in place ofthe new host compound 1-5 of Example 1.

[Evaluation on Emitting Performance of Organic EL Device]

The organic EL devices according to Examples 1 to 10 and Comparatives 1to 3 each were driven by direct-current electricity to emit light, sothat voltage at a current density of 10 mA/cm², luminous efficiency andtime elapsed until the initial luminance intensity of 3000 cd/m² wasreduced to the half (i.e., time until half-life) were measured for eachorganic EL device. Then, pixel uniformity when each organic EL devicewas driven at 70 degrees C. was visually checked, among which deviceshaving uniform pixels are rated as A while devices having ununiformpixels are rated as B. The results of the evaluation are shown in Table1.

TABLE 1 Lumi- Time Pixel Uni- nous until formity Ef- Half- When HostVoltage ficiency Life Driven Compound (V) (cd/A) (hours) at 70° C.Example 1 1-5 4.2 9.4 10000 A Example 2 1-9 4.2 10.8 9500 A Example 31-11 4.5 11.2 8000 A Example 4 1-17 4.1 8.8 9000 A Example 5 1-18 4.18.5 10000 A Example 6 1-21 4.8 10.7 10000 A Example 7 1-30 5.0 11.310000 A Example 8 1-33 4.6 10.6 10000 A Example 9 1-37 5.1 11.5 8000 AExample 10 1-39 4.8 11.1 9000 A Comparative 1 CBP 5.4 6.3 1200 BComparative 2 Compound A 5.5 8.3 800 B Comparative 3 Compound B 4.8 8.1500 B

As is understood from the above, the organic EL device according to eachof Examples 1 to 10, in which the naphthalene derivative according tothe present invention was used as the host of the phosphorescentemitting layer, is excellent in time until half-life, pixel uniformitywhen driven at a high temperature of 70 degrees C. and luminousefficiency, and requires less drive voltage, as compared with theorganic EL device according to each of Comparatives 1 to 3.

Accordingly, the organic EL device according to the present invention isfree from pixel defects and excellent in luminous efficiency, heatresistance and lifetime.

The priority application Numbers JP2007-179120 and JP2007-179121 uponwhich this patent application is based are hereby incorporated byreference.

1. A naphthalene derivative represented by a formula (1)

wherein Ar¹ to Ar⁶ each represent a substituted or unsubstitutedaromatic hydrocarbon cyclic group having 6 to 18 carbon atoms forming aring, the substituted or unsubstituted aromatic hydrocarbon cyclic grouphaving none of anthracene skeleton, pyrene skeleton, aceanthryleneskeleton and naphthacene skeleton, Ar¹ and Ar² each being allowed to bebonded in any position of a benzene skeleton; R¹ to R³ each represent analkyl group, a cycloalkyl group, an alkoxy group, a cyano group, a silylgroup or a halogen atom, R¹ to R³ each being allowed to be bonded in anyposition of a main-chain naphthalene skeleton or a main-chain benzeneskeleton; a and b each represent an integer in a range of 0 to 4; arepresents the number of substituent(s) R¹ directly bonded to themain-chain benzene; b represents the number of substituent(s) R²directly bonded to the main-chain naphthalene; c represents the numberof substituent(s) R³ directly bonded to the main-chain benzene; l, m, nand p each represent 0 or 1; R¹, R² and R³ each are allowed to bemutually the same or different; when a, b and c each are 2 or more, theplurality of R¹ are allowed to be mutually the same or different, theplurality of R² are allowed to be mutually the same or different, theplurality of R³ are allowed to be mutually the same or different or thepluralities of R¹ to R³ are allowed to be the same as or different fromone another; Ar¹ to Ar⁶ are allowed to mutually the same or different;when at least either one of l and n is 1, Ar¹ represents neither abenzene skeleton nor a naphthalene skeleton; when at least either one ofm and p is 1, Ar² represents neither a benzene skeleton nor anaphthalene skeleton; the structure represented by(H—[Ar⁵]_(n)—[Ar³]_(l)—Ar¹—) is not the same as the structurerepresented by (H—[Ar⁶]_(p)—[Ar⁴]_(m)—Ar²—); when the naphthalenederivative has a structure in which two naphthalene skeletons areconsecutively bonded together, the structure of the naphthalenederivative is represented by any one of formulae (1-A), (1-B), (1-C) and(1-D)

the naphthalene skeletons represented by the formulae (1-A), (1-B) and(1-C) each are allowed to have a substituent(s) in any suitableposition(s) or unsubstituted; R in the formula (1-D) represents asubstituent, R being allowed to represent a single substituent or pluralsubstituents, the single substituent or the plural substituents beingallowed to be in any position(s) of the two naphthalene skeletons, theplural substituents when R represents the plural substituents beingallowed to be mutually the same or different; when the naphthalenederivative contains a plurality of unsubstituted 9-phenanthrenes, thenumber of the unsubstituted 9-phenanthrenes is 3 or more; and when Ar¹to Ar⁶ each represent a phenanthrene skeleton, the phenanthrene skeletonis monovalent phenanthrene.
 2. The naphthalene derivative according toclaim 1, wherein Ar¹ to Ar⁶ in the formula (1) each represent a benzeneskeleton, a naphthalene skeleton, a fluorene skeleton, a phenanthreneskeleton, a fluoranthene skeleton, a triphenylene skeleton or a chryseneskeleton.
 3. The naphthalene derivative according to claim 2, wherein,when Ar¹ to Ar⁶ in the formula (1) each has a substituent, thesubstituent represented by each of Ar¹ to Ar⁶ is selected from a groupconsisting of an aryl group, an alkyl group, a cycloalkyl group, analkoxy group, a cyano group, a silyl group and a halogen atom.
 4. Thenaphthalene derivative according to claim 1, wherein a sum of m, n, 1and p in the formula (1) is in a range of 0 to
 3. 5. The naphthalenederivative according to claim 1, wherein a, b and c in the formula (1)each represent an integer in a range of 0 to
 3. 6. The naphthalenederivative according to claim 1, wherein a, b and c in the formula (1)each are
 0. 7. A material for an organic electroluminescence device, thematerial comprising the naphthalene derivative according to claim
 1. 8.The material for an organic electroluminescence device according toclaim 7, the material being used together with a phosphorescentmaterial.
 9. The material for an organic electroluminescence deviceaccording to claim 7, the material being used as a host material for anemitting layer. 10-16. (canceled)